Encoder and decoder, encoding method and decoding method with complexity handling for flexibly sized picture partitions

ABSTRACT

A video encoder according to embodiments is provided. The video encoder is configured for encoding a plurality of pictures of a video by generating an encoded video signal, wherein each of the plurality of pictures has original picture data. The video encoder has a data encoder configured for generating the encoded video signal having encoded picture data, wherein the data encoder is configured to encode the plurality of pictures of the video into the encoded picture data. Moreover, the video encoder has an output interface configured for outputting the encoded picture data of each of the plurality of pictures. Furthermore, a video decoders, systems, methods for encoding and decoding, computer programs and encoded video signals according to embodiments are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.16/777,180, pending, which claims priority from European Application No.18248303.2, filed Dec. 28, 2018, the content of each of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to video encoding and video decoding and,in particular, to an encoder and a decoder, to an encoding method and toa decoding method with complexity handling for flexibly sized picturedata.

H.265/HEVC (HEVC = High Efficiency Video Coding) is a video codec whichalready provides tools for elevating or even enabling parallelprocessing at an encoder and/or at a decoder. For example, HEVC supportsa sub-division of pictures into an array of tiles which are encodedindependently from each other. Another concept supported by HEVCpertains to WPP, according to which CTU-rows or CTU-lines of thepictures may be processed in parallel from left to right, e.g. instripes, provided that some minimum CTU offset is obeyed in theprocessing of consecutive CTU lines (CTU = coding tree unit). It wouldbe favorable, however, to have a video codec at hand which supportsparallel processing capabilities of video encoders and/or video decoderseven more efficiently.

In the following, an introduction to VCL partitioning according to thestate-of-the-art is described (VCL ₌ video coding layer).

Typically, in video coding, a coding process of picture samples usessmaller partitions, where samples are divided into some rectangularareas for joint processing such as prediction or transform coding.Therefore, a picture is partitioned into blocks of a particular sizethat is constant during encoding of the video sequence. In H.264/AVCstandard fixed-size blocks of 16×16 samples, so called macroblocks, areused (AVC = Advanced Video Coding).

In the state-of-the-art HEVC standard (see [1]), there are Coded TreeBlocks (CTB) or Coding Tree Units (CTU) of a maximum size of 64 × 64samples. In the further description of HEVC, for such a kind of blocks,the more common term CTU is used.

CTUs are processed in raster scan order, starting with the top-left CTU,processing CTUs in the picture line-wise, down to the bottom-right CTU.

The coded CTU data is organized into a kind of container called slice.Originally, in former video coding standards, slice means a segmentcomprising one or more consecutive CTUs of a picture. Slices areemployed for a segmentation of coded data. From another point of view,the complete picture can also be defined as one big segment and hence,historically, the term slice is still applied. Besides the coded picturesamples, slices also comprise additional information related to thecoding process of the slice itself which is placed into a so-calledslice header.

According to the state-of-the-art, a VCL (video coding layer) alsocomprises techniques for fragmentation and spatial partitioning. Suchpartitioning may, e.g., be applied in video coding for various reasons,among which are processing load-balancing in parallelization, CTU sizematching in network transmission, error-mitigation etc.

SUMMARY

According to an embodiment, a video encoder for encoding a plurality ofpictures of a video by generating an encoded video signal, wherein eachof the plurality of pictures has original picture data, may have: a dataencoder configured for generating the encoded video signal havingencoded picture data, wherein the data encoder is configured to encodethe plurality of pictures of the video into the encoded picture data,and an output interface configured for outputting the encoded picturedata of each of the plurality of pictures, wherein, for each picture ofthe plurality of pictures, the data encoder is configured to partitionthe picture into a plurality of tiles having a plurality of coding treeunits of the picture, wherein each coding tree unit of the plurality ofcoding tree units has a plurality of samples of the picture, wherein,for each picture of the plurality of pictures, the data encoder isconfigured to encode the original picture data of each of the pluralityof tiles of the picture, wherein the data encoder is configured togenerate the encoded video signal such that the encoded video signalfurther has a first flag that indicates for a current picture of theplurality of pictures, whether a reference picture of the plurality ofpictures being different from the current picture has been used forencoding the current picture.

According to another embodiment, a video decoder for decoding an encodedvideo signal having encoded picture data to reconstruct a plurality ofpictures of a video may have: an input interface configured forreceiving the encoded video signal, and a data decoder configured forreconstructing the plurality of pictures of the video by decoding theencoded picture data, wherein, for each picture of the plurality ofpictures, the picture is partitioned into a plurality of tiles having aplurality of coding tree units of the picture, wherein each coding treeunit of the plurality of coding tree units has a plurality of samples ofthe picture, wherein the encoded video signal further has a first flagthat indicates for a current picture of the plurality of pictures,whether a reference picture of the plurality of pictures being differentfrom the current picture has been used for encoding the current picture,wherein, for a picture of the plurality of pictures, the data decoder isconfigured to decode the encoded picture data of each of the pluralityof tiles of the picture depending on the first flag to obtain originalpicture data of the plurality of coding tree units of each of theplurality of pictures.

According to another embodiment, a method for encoding a plurality ofpictures of a video by generating an encoded video signal, wherein eachof the plurality of pictures has original picture data, may have thesteps of: generating the encoded video signal having encoded picturedata, wherein the data encoder is configured to encode the plurality ofpictures of the video into the encoded picture data, and outputting theencoded picture data of each of the plurality of pictures, wherein themethod may further have the step of: for each picture of the pluralityof pictures, partitioning the picture into a plurality of tiles having aplurality of coding tree units of the picture, wherein each coding treeunit of the plurality of coding tree units has a plurality of samples ofthe picture, for each picture of the plurality of pictures, encoding theoriginal picture data of each of the plurality of tiles of the picture,and wherein generating the encoded video signal is conducted such thatthe encoded video signal further has a first flag that indicates for acurrent picture of the plurality of pictures, whether a referencepicture of the plurality of pictures being different from the currentpicture has been used for encoding the current picture.

According to still another embodiment, a method for decoding an encodedvideo signal having encoded picture data to reconstruct a plurality ofpictures of a video may have the steps of: receiving the encoded videosignal, and reconstructing the plurality of pictures of the video bydecoding the encoded picture data, wherein, for each picture of theplurality of pictures, the picture is partitioned into a plurality oftiles having a plurality of coding tree units of the picture, whereineach coding tree unit of the plurality of coding tree units has aplurality of samples of the picture, wherein the encoded video signalfurther has a first flag that indicates for a current picture of theplurality of pictures, whether a reference picture of the plurality ofpictures being different from the current picture has been used forencoding the current picture, wherein, for a picture of the plurality ofpictures, decoding the encoded picture data of each of the plurality oftiles of the picture is conducted depending on the first flag to obtainoriginal picture data of the plurality of coding tree units of each ofthe plurality of pictures.

Another embodiment may have a non-transitory digital storage mediumhaving stored thereon a computer program for performing a method forencoding a plurality of pictures of a video by generating an encodedvideo signal, wherein each of the plurality of pictures has originalpicture data, wherein the method may have the steps of: generating theencoded video signal having encoded picture data, wherein the dataencoder is configured to encode the plurality of pictures of the videointo the encoded picture data, and outputting the encoded picture dataof each of the plurality of pictures, wherein the method may furtherhave the steps of: for each picture of the plurality of pictures,partitioning the picture into a plurality of tiles having a plurality ofcoding tree units of the picture, wherein each coding tree unit of theplurality of coding tree units has a plurality of samples of thepicture, for each picture of the plurality of pictures, encoding theoriginal picture data of each of the plurality of tiles of the picture,and wherein generating the encoded video signal is conducted such thatthe encoded video signal further has a first flag that indicates for acurrent picture of the plurality of pictures, whether a referencepicture of the plurality of pictures being different from the currentpicture has been used for encoding the current picture, when saidcomputer program is run by a computer.

Another embodiment may have a non-transitory digital storage mediumhaving stored thereon a computer program for performing a method fordecoding an encoded video signal having encoded picture data toreconstruct a plurality of pictures of a video, wherein the method mayhave the steps of: receiving the encoded video signal, andreconstructing the plurality of pictures of the video by decoding theencoded picture data, wherein, for each picture of the plurality ofpictures, the picture is partitioned into a plurality of tiles having aplurality of coding tree units of the picture, wherein each coding treeunit of the plurality of coding tree units has a plurality of samples ofthe picture, wherein the encoded video signal further has a first flagthat indicates for a current picture of the plurality of pictures,whether a reference picture of the plurality of pictures being differentfrom the current picture has been used for encoding the current picture,wherein, for a picture of the plurality of pictures, decoding theencoded picture data of each of the plurality of tiles of the picture isconducted depending on the first flag to obtain original picture data ofthe plurality of coding tree units of each of the plurality of pictures,when said computer program is run by a computer.

Still another embodiment may have an encoded video signal encoding apicture, wherein the encoded video signal has encoded picture dataencoding the picture, wherein, for each picture of the plurality ofpictures, the picture is partitioned into a plurality of tiles having aplurality of coding tree units of the picture, wherein each coding treeunit of the plurality of coding tree units has a plurality of samples ofthe picture, wherein, for each picture of the plurality of pictures, theoriginal picture data of each of the plurality of tiles of the pictureis encoded within the encoded video signal, and wherein the encodedvideo signal further has a first flag that indicates for a currentpicture of the plurality of pictures, whether a reference picture of theplurality of pictures being different from the current picture has beenused for encoding the current picture.

According to another embodiment, a system may have: the inventive videoencoder as mentioned above, and the inventive video decoder as mentionedabove, wherein the video encoder configured to generate the encodedvideo signal, and wherein the video decoder is configured to decode theencoded video signal to reconstruct the picture of the video.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, embodiments of the present invention are described indetail with reference to the figures, in which:

FIG. 1 illustrates a video encoder according to an embodiment;

FIG. 2 illustrates a video decoder according to an embodiment;

FIG. 3 illustrates a system according to an embodiment;

FIG. 4 illustrates CTUs affected by displacing a partial CTU creatingtile boundary;

FIG. 5 illustrates luma sample per picture compensation from partialCTUs;

FIG. 6 illustrates CTU grid alignment mismatches;

FIG. 7 illustrates a rate of grid mismatch affected CTUs;

FIG. 8 illustrates two sets of tile boundaries;

FIG. 9 illustrates corresponding CTU rows in reference picture afterpartial CTU in current picture;

FIG. 10 illustrates a video encoder;

FIG. 11 illustrates a video decoder;

FIG. 12 illustrates the relationship between the reconstructed signal,i.e. the reconstructed picture, on the one hand, and the combination ofthe prediction residual signal as signaled in the data stream, and theprediction signal, on the other hand;

FIG. 13 illustrates picture segmentation with slices in raster scanorder; and

FIG. 14 illustrates picture partitioning with tiles.

DETAILED DESCRIPTION OF THE INVENTION

The following description of the figures starts with a presentation of adescription of an encoder and a decoder of a block-based predictivecodec for coding pictures of a video in order to form an example for acoding framework into which embodiments of the present invention may bebuilt in. The respective encoder and decoder are described with respectto FIG. 10 to FIG. 12 . Thereinafter the description of embodiments ofthe concept of the present invention is presented along with adescription as to how such concepts could be built into the encoder anddecoder of FIG. 10 and FIG. 11 , respectively, although the embodimentsdescribed with FIG. 1 to FIG. 3 and following, may also be used to formencoders and decoders not operating according to the coding frameworkunderlying the encoder and decoder of FIG. 10 and FIG. 11 .

FIG. 10 shows a video encoder, an apparatus for predictively coding apicture 12 into a data stream 14 exemplarily using transform-basedresidual coding. The apparatus, or encoder, is indicated using referencesign 10. FIG. 11 shows a corresponding video decoder 20, i.e. anapparatus 20 configured to predictively decode the picture 12′ from thedata stream 14 also using transform-based residual decoding, wherein theapostrophe has been used to indicate that the picture 12′ asreconstructed by the decoder 20 deviates from picture 12 originallyencoded by apparatus 10 in terms of coding loss introduced by aquantization of the prediction residual signal. FIG. 10 and FIG. 11exemplarily use transform based prediction residual coding, althoughembodiments of the present application are not restricted to this kindof prediction residual coding. This is true for other details describedwith respect to FIG. 10 and FIG. 11 , too, as will be outlinedhereinafter.

The encoder 10 is configured to subject the prediction residual signalto spatial-to-spectral transformation and to encode the predictionresidual signal, thus obtained, into the data stream 14. Likewise, thedecoder 20 is configured to decode the prediction residual signal fromthe data stream 14 and subject the prediction residual signal thusobtained to spectral-to-spatial transformation.

Internally, the encoder 10 may comprise a prediction residual signalformer 22 which generates a prediction residual 24 so as to measure adeviation of a prediction signal 26 from the original signal, i.e. fromthe picture 12. The prediction residual signal former 22 may, forinstance, be a subtractor which subtracts the prediction signal from theoriginal signal, i.e. from the picture 12. The encoder 10 then furthercomprises a transformer 28 which subjects the prediction residual signal24 to a spatial-to-spectral transformation to obtain a spectral-domainprediction residual signal 24′ which is then subject to quantization bya quantizer 32, also comprised by the encoder 10. The thus quantizedprediction residual signal 24″ is coded into bitstream 14. To this end,encoder 10 may optionally comprise an entropy coder 34 which entropycodes the prediction residual signal as transformed and quantized intodata stream 14. The prediction signal 26 is generated by a predictionstage 36 of encoder 10 on the basis of the prediction residual signal24″ encoded into, and decodable from, data stream 14. To this end, theprediction stage 36 may internally, as is shown in FIG. 10 , comprise adequantizer 38 which dequantizes prediction residual signal 24″ so as togain spectral-domain prediction residual signal 24‴, which correspondsto signal 24′ except for quantization loss, followed by an inversetransformer 40 which subjects the latter prediction residual signal 24‴to an inverse transformation, i.e. a spectral-to-spatial transformation,to obtain prediction residual signal 24⁗, which corresponds to theoriginal prediction residual signal 24 except for quantization loss. Acombiner 42 of the prediction stage 36 then recombines, such as byaddition, the prediction signal 26 and the prediction residual signal24⁗ so as to obtain a reconstructed signal 46, i.e. a reconstruction ofthe original signal 12. Reconstructed signal 46 may correspond to signal12′. A prediction module 44 of prediction stage 36 then generates theprediction signal 26 on the basis of signal 46 by using, for instance,spatial prediction, i.e. intra-picture prediction, and/or temporalprediction, i.e. inter-picture prediction.

Likewise, decoder 20, as shown in FIG. 11 , may be internally composedof components corresponding to, and interconnected in a mannercorresponding to, prediction stage 36. In particular, entropy decoder 50of decoder 20 may entropy decode the quantized spectral-domainprediction residual signal 24″ from the data stream, whereupondequantizer 52, inverse transformer 54, combiner 56 and predictionmodule 58, interconnected and cooperating in the manner described abovewith respect to the modules of prediction stage 36, recover thereconstructed signal on the basis of prediction residual signal 24″ sothat, as shown in FIG. 11 , the output of combiner 56 results in thereconstructed signal, namely picture 12′.

Although not specifically described above, it is readily clear that theencoder 10 may set some coding parameters including, for instance,prediction modes, motion parameters and the like, according to someoptimization scheme such as, for instance, in a manner optimizing somerate and distortion related criterion, i.e. coding cost. For example,encoder 10 and decoder 20 and the corresponding modules 44, 58,respectively, may support different prediction modes such asintra-coding modes and inter-coding modes. The granularity at whichencoder and decoder switch between these prediction mode types maycorrespond to a subdivision of picture 12 and 12′, respectively, intocoding segments or coding blocks. In units of these coding segments, forinstance, the picture may be subdivided into blocks being intra-codedand blocks being inter-coded. Intra-coded blocks are predicted on thebasis of a spatial, already coded/decoded neighborhood of the respectiveblock as is outlined in more detail below. Several intra-coding modesmay exist and be selected for a respective intra-coded segment includingdirectional or angular intra-coding modes according to which therespective segment is filled by extrapolating the sample values of theneighborhood along a certain direction which is specific for therespective directional intra-coding mode, into the respectiveintra-coded segment. The intra-coding modes may, for instance, alsocomprise one or more further modes such as a DC coding mode, accordingto which the prediction for the respective intra-coded block assigns aDC value to all samples within the respective intra-coded segment,and/or a planar intra-coding mode according to which the prediction ofthe respective block is approximated or determined to be a spatialdistribution of sample values described by a two-dimensional linearfunction over the sample positions of the respective intra-coded blockwith driving tilt and offset of the plane defined by the two-dimensionallinear function on the basis of the neighboring samples. Comparedthereto, inter-coded blocks may be predicted, for instance, temporally.For inter-coded blocks, motion vectors may be signaled within the datastream, the motion vectors indicating the spatial displacement of theportion of a previously coded picture of the video to which picture 12belongs, at which the previously coded/decoded picture is sampled inorder to obtain the prediction signal for the respective inter-codedblock. This means, in addition to the residual signal coding comprisedby data stream 14, such as the entropy-coded transform coefficientlevels representing the quantized spectral-domain prediction residualsignal 24″, data stream 14 may have encoded thereinto coding modeparameters for assigning the coding modes to the various blocks,prediction parameters for some of the blocks, such as motion parametersfor inter-coded segments, and optional further parameters such asparameters for controlling and signaling the subdivision of picture 12and 12′, respectively, into the segments. The decoder 20 uses theseparameters to subdivide the picture in the same manner as the encoderdid, to assign the same prediction modes to the segments, and to performthe same prediction to result in the same prediction signal.

FIG. 12 illustrates the relationship between the reconstructed signal,i.e. the reconstructed picture 12′, on the one hand, and the combinationof the prediction residual signal 24⁗ as signaled in the data stream 14,and the prediction signal 26, on the other hand. As already denotedabove, the combination may be an addition. The prediction signal 26 isillustrated in FIG. 12 as a subdivision of the picture area intointra-coded blocks which are illustratively indicated using hatching,and inter-coded blocks which are illustratively indicated not-hatched.The subdivision may be any subdivision, such as a regular subdivision ofthe picture area into rows and columns of square blocks or non-squareblocks, or a multi-tree subdivision of picture 12 from a tree root blockinto a plurality of leaf blocks of varying size, such as a quadtreesubdivision or the like, wherein a mixture thereof is illustrated inFIG. 12 in which the picture area is first subdivided into rows andcolumns of tree root blocks which are then further subdivided inaccordance with a recursive multi-tree subdivisioning into one or moreleaf blocks.

Again, data stream 14 may have an intra-coding mode coded thereinto forintra-coded blocks 80, which assigns one of several supportedintra-coding modes to the respective intra-coded block 80. Forinter-coded blocks 82, the data stream 14 may have one or more motionparameters coded thereinto. Generally speaking, inter-coded blocks 82are not restricted to being temporally coded. Alternatively, inter-codedblocks 82 may be any block predicted from previously coded portionsbeyond the current picture 12 itself, such as previously coded picturesof a video to which picture 12 belongs, or picture of another view or anhierarchically lower layer in the case of encoder and decoder beingscalable encoders and decoders, respectively.

The prediction residual signal 24⁗ in FIG. 12 is also illustrated as asubdivision of the picture area into blocks 84. These blocks might becalled transform blocks in order to distinguish same from the codingblocks 80 and 82. In effect, FIG. 12 illustrates that encoder 10 anddecoder 20 may use two different subdivisions of picture 12 and picture12′, respectively, into blocks, namely one subdivisioning into codingblocks 80 and 82, respectively, and another subdivision into transformblocks 84. Both subdivisions might be the same, i.e. each coding block80 and 82, may concurrently form a transform block 84, but FIG. 12illustrates the case where, for instance, a subdivision into transformblocks 84 forms an extension of the subdivision into coding blocks 80,82 so that any border between two blocks of blocks 80 and 82 overlays aborder between two blocks 84, or alternatively speaking each block 80,82 either coincides with one of the transform blocks 84 or coincideswith a cluster of transform blocks 84. However, the subdivisions mayalso be determined or selected independent from each other so thattransform blocks 84 could alternatively cross block borders betweenblocks 80, 82. As far as the subdivision into transform blocks 84 isconcerned, similar statements are thus true as those brought forwardwith respect to the subdivision into blocks 80, 82, i.e. the blocks 84may be the result of a regular subdivision of picture area into blocks(with or without arrangement into rows and columns), the result of arecursive multi-tree subdivisioning of the picture area, or acombination thereof or any other sort of blockation. Just as an aside,it is noted that blocks 80, 82 and 84 are not restricted to being ofquadratic, rectangular or any other shape.

FIG. 12 further illustrates that the combination of the predictionsignal 26 and the prediction residual signal 24⁗ directly results in thereconstructed signal 12′. However, it should be noted that more than oneprediction signal 26 may be combined with the prediction residual signal24⁗ to result into picture 12′ in accordance with alternativeembodiments.

In FIG. 12 , the transform blocks 84 shall have the followingsignificance. Transformer 28 and inverse transformer 54 perform theirtransformations in units of these transform blocks 84. For instance,many codecs use some sort of DST or DCT for all transform blocks 84.Some codecs allow for skipping the transformation so that, for some ofthe transform blocks 84, the prediction residual signal is coded in thespatial domain directly. However, in accordance with embodimentsdescribed below, encoder 10 and decoder 20 are configured in such amanner that they support several transforms. For example, the transformssupported by encoder 10 and decoder 20 could comprise:

-   DCT-II (or DCT-III), where DCT stands for Discrete Cosine Transform-   DST-IV, where DST stands for Discrete Sine Transform-   DCT-IV-   DST-VII-   Identity Transformation (IT)

Naturally, while transformer 28 would support all of the forwardtransform versions of these transforms, the decoder 20 or inversetransformer 54 would support the corresponding backward or inverseversions thereof:

-   Inverse DCT-II (or inverse DCT-III)-   Inverse DST-IV-   Inverse DCT-IV-   Inverse DST-VII-   Identity Transformation (IT)

The subsequent description provides more details on which transformscould be supported by encoder 10 and decoder 20. In any case, it shouldbe noted that the set of supported transforms may comprise merely onetransform such as one spectral-to-spatial or spatial-to-spectraltransform.

As already outlined above, FIG. 10 to FIG. 12 have been presented as anexample where the inventive concept described further below may beimplemented in order to form specific examples for encoders and decodersaccording to the present application. Insofar, the encoder and decoderof FIG. 10 and FIG. 11 , respectively, may represent possibleimplementations of the encoders and decoders described herein below.FIG. 10 and FIG. 11 are, however, only examples. An encoder according toembodiments of the present application may, however, perform block-basedencoding of a picture 12 using the concept outlined in more detail belowand being different from the encoder of FIG. 10 such as, for instance,in that same is no video encoder, but a still picture encoder, in thatsame does not support inter-prediction, or in that the sub-division intoblocks 80 is performed in a manner different than exemplified in FIG. 12. Likewise, decoders according to embodiments of the present applicationmay perform block-based decoding of picture 12′ from data stream 14using the coding concept further outlined below, but may differ, forinstance, from the decoder 20 of FIG. 11 in that same is no videodecoder, but a still picture decoder, in that same does not supportintra-prediction, or in that same subdivides picture 12′ into blocks ina manner different than described with respect to FIG. 12 and/or in thatsame does not derive the prediction residual from the data stream 14 intransform domain, but in spatial domain, for instance.

Picture partitioning with slices is now briefly described.

Beginning with the H.263 standard, the sequence of data representingcontiguous blocks in a particular scan order can be organized intogroups called slices. Typically, the dependencies between CTUs ofdifferent slices of a picture, e.g. in terms of prediction and entropycoding, are prohibited, so individual slices within a picture can beindependently reconstructed.

FIG. 13 illustrates picture segmentation with slices in raster scanorder. The size of a slice is determined by the number of CTUs (codingtree units) and the size of each coded CTU that belongs to a slice asillustrated in FIG. 13 . FIG. 13 comprises 50 CTUs, for example, CTU221, CTU 224 and CTU 251.

Picture partitioning with tiles is now briefly described with referenceto FIG. 14 . FIG. 14 comprises 50 CTUs, for example, CTU 223, CTU 227and CTU 241.

Tiles are a concept introduced in HEVC, although the concept is a quitesimilar to Flexible Macroblock Ordering (FMO) was added to H.264/AVC.The concept of tiles allows dividing the picture into severalrectangular regions.

Tiles are thus a result of dividing the original picture into a givennumber of rows and columns with a specified height and widthrespectively as illustrated in FIG. 14 . As a result of that, tileswithin an HEVC bitstream are to have common boundaries that form aregular grid.

In the following, a generic video encoder according to embodiments isdescribed in FIG. 1 , a generic video decoder according to embodimentsis described in FIG. 2 , and a generic system according to embodimentsis described in FIG. 3 .

FIG. 1 illustrates a generic video encoder 101 according to embodiments.

The video encoder 101 is configured for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data.

The video encoder 101 comprises a data encoder 110 configured forgenerating the encoded video signal comprising encoded picture data,wherein the data encoder is configured to encode the plurality ofpictures of the video into the encoded picture data.

Moreover, the video encoder 101 comprises an output interface 120configured for outputting the encoded picture data of each of theplurality of pictures.

FIG. 2 illustrates a generic video decoder 151 according to embodiments.

The video decoder 151 is configured for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video.

The video decoder 151 comprises an input interface 160 configured forreceiving the encoded video signal.

Moreover, the video decoder comprises a data decoder 170 configured forreconstructing the plurality of pictures of the video by decoding theencoded picture data.

FIG. 3 illustrates a generic system according to embodiments.

The system comprises the video encoder 101 of FIG. 1 and the videodecoder 151 of FIG. 2 .

The video encoder 101 is configured to generate the encoded videosignal. The video decoder 151 is configured to decode the encoded videosignal to reconstruct the picture of the video.

A first aspect is provided in examples 1 to 5, in examples 45 to 49 andin examples 89 to 93.

A second aspect is provided in examples 6 to 13, in examples 50 to 57and in examples 94 to 98.

A third aspect is provided in examples 14 to 18, in examples 58 to 62and in examples 99 to 103.

A fourth aspect is provided in examples 19 to 22, in examples 63 to 66and in examples 104 to 108.

A fifth aspect is provided in examples 24 to 27, in examples 68 to 71and in examples 109 to 113.

A sixth aspect is provided in examples 28 to 32, in examples 72 to 76and in examples 114 to 118.

A seventh aspect is provided in examples 33 and 34, in examples 77 and78 and in examples 119 to 123.

An eighth aspect is provided in examples 35 to 38, in examples 79 to 82and in examples 124 to 128.

A ninth aspect is provided in examples 40 to 44, in examples 84 to 88and in examples 129 to 133.

Examples 23, 39, 67 and 83 relate to particular examples that may, forexample, be employed for different aspects.

In the following, details of complexity handling for flexibly sizedpicture partitions according to embodiments are described.

Tiles have been specified in HEVC as a subdivision mechanism for thepicture. They are defined in the picture parameter set (PPS), wheretheir dimensions are given. Tiles, as defined for now have a size whichis multiple of CTUs (typically 64 samples) and only the last tiles, i.e.tiles at the right or bottom border, of a picture are allowed to havetheir CTUs at the right and bottom picture boundaries being smaller than64.

However, such a restriction prevents a couple of use-cases:

MCTS bitstream merging: the bitstreams to be merged together within asingle bitstream need to be a multiple of the size chose for the CTU, asoriginal picture boundaries might not be picture boundaries in themerged bitstream.

Proper load balancing, where tiles adjust to the content not necessarilyat multiples of a predefined size (the CTU size)

In addition, the current video coding specification developed by JVET -Versatile Video Coding - allows larger values of CTUs (up to 128), whichmakes it even more crucial to allow for tiles that are not multiple ofCTUs. Defining partial CTUs based on whether the desired functionalityis used, would be possible but would affect the coding efficiency forsuch cases. Still, it is desirable to allow tiles to not comprise acomplete number of CTUs of a determined size but to allow the rightmostCTUs and CTUs on the bottom boundary of a tiles to be smaller.

However, when such a functionality is allowed, different aspects affectthe decoding process.

In the following, controlling the complexity of partial in-picture CTUsis described.

In particular, the first aspect of the invention is now described indetail:

Currently, that all CTUs are the same size, processors are optimized todecode the structures of the predefined size. Allowing that variablesize might impose a complexity increase for a decoder. Especially, sincethe number of CTUs can change from picture to picture.

The first aspect of the current invention is that when such variablesized CTUs are allowed within each tile, a constraint need to befulfilled that keeps the number of variable sized CTUs constant frompicture to picture.

In the first aspect, a constraint is applied.

FIG. 4 illustrates CTUs affected by displacing a partial CTU creatingtile boundary.

If tiles sizes are not multiple of the predefined CTU size, hencevariable sized CTUs smaller than the predefined CTU size are introduced,it is a requirement of bitstream conformance to have the same number ofsuch variable sized CTUs in each of the pictures as illustrated in FIG.4 .

Additionally, this property can be signaled to a decoder using a flag ina parameter set that indicates num_partial_ctus_constant_flag.

The second aspect of the invention is now described in detail:

The second aspect differentiates partial CTUs creating tile boundariesfrom regular tile boundaries in their complexity impact. When decoderchecks level limitations for maximum amount of decoded pels per timeunit, it adds a complexity factor for partial CTUs. For example, thepartial CTU could be counted with 1.5 times it’s actual size, or withthe number of pels of the predetermined CTU size as if it were not to belimited in size to be a variable sized CTU by a tile boundary. Thismeans that picture size limits could be affected by the presence ofpartial CTUs. For instance, if all CTUs are of the same size a picturelimit for a decoder can be 4096×2160 at 50 frames per second, but if 5×4tiles where defined and all would have partial CTUs at the right andbottom boundaries, i.e. 20 partial CTUs, then the limit could be4056×2128 at the same frame rate.

FIG. 5 illustrates luma sample per picture compensation from partialCTUs. In particular, the complexity adjusted picture area is illustratedin FIG. 5 .

Furthermore, a lower limit to the size of variable sized CTUs is imposedto regard the granularity with which motion vector or displacementinformation of reference pictures is stored in the coding process, e.g.with a 16×16 samples granularity, as opposed to allow arbitrarily smallvariable CTUs with a size between 1 sample and a predefined CTU size inany direction. A variable sized CTU is not allowed to be smaller than apredetermined minimal CTU size to be indicated or derived, e.g. from themotion vector storage granularity so that no two CTUs lie within thescope of the same motion vector storage unit.

The third aspect of the invention is now described in detail:

In such another independent third aspect, the presence of partial CTUsis taken into account for the complexity signaling of tiles. Forinstance, HEVC comprises the parameters min_spatial_segmentation_idc inVUI that describe the complexity of spatial segments including tiles.Currently, when applied to tiles it implies that “there is no tile inthe CVS (coded video sequence) that comprises more than ( 4 *PicSizeInSamplesY ) / (min_spatial_segmentation_idc+4) luma samples”. Inaddition, as part of the invention, the complexity signaling limits fortiles to not comprise more than a given number of partial CTUs dependingon the maximum tile size and/or relationship between the default CTUsize and the size of partial CTUs. Alternatively, an additionalparameter is signaled in VUI indicating the relative amount of partialCTUs allowed in a picture.

In the following, embodiments are described where CTU boundaries canchange from picture to picture.

In particular, the fourth aspect of the invention is now described indetail:

If tiles might have their right/bottom boundaries end at smallergranularity than the pre-defined CTU size, and following tiles startwith CTUs at pre-defined size, when the tiles setup changes from pictureto picture, CTU alignment across pictures will not be achieved, whichmight be detrimental for some predictive coding, such as using temporalmotion vector prediction. Memory management could be more difficult andtherefore, it would be desirable to limit the flexibility of generatingCTU boundary misalignment from picture to picture.

The fourth aspect would be to constrain that any tile boundary, thatcreates partial CTUs, can only be moved to a location, at which itcreates partial CTUs at same split ratio at a different picture withinthe same video sequence. This allows for having aligned CTUs in areasnot covered by the range from initial last CTU position and modifiedlast CTU position as illustrated FIG. 6 .

FIG. 6 illustrates CTU grid alignment mismatches.

The fifth aspect of the invention is now described in detail:

In the fifth aspect, a limitation is applied for the rate of blocks, inwhich with grid mismatches may occur between pictures with changingpartial tile boundaries as illustrated in FIG. 7 . This constraint mayeither be defined in a default manner for a given profile/level, orindicated as a syntax element in the bitstream, e.g.num_misaligned_ctus_per_picture. FIG. 7 illustrates a rate of gridmismatch affected CTUs.

Alternatively, the constraint described here, where the number ofpartial (boundary) CTUs stays constant and with same ratio, can beimplemented as a simple constraint indication, e.g.misalignment_constant_flag, where indication of tile boundaries staysflexible but has to fulfill the constraint or can be achieved by a lessflexible manner.

The sixth aspect of the invention is now described in detail:

In the sixth aspect, CTU misalignment is completely avoided: two set oftile boundaries are defined. The first set of tile boundariescorresponds to traditional tile boundaries:

-   Entropy coding reset-   Intra prediction constraints-   Scan order change

And in addition, tiles of the first set allow creating partial CTUs atthe right and bottom tile boundaries.

The second set of tile boundaries does solely create partial CTUs at theright and/or bottom tile boundaries, i.e. to the left and/or above ofsaid tile boundaries and does not imply entropy coding reset, intraprediction or a change in scan order. Thereby, the location of partialCTUs within the picture can (and is constraint to) remain static whileactual tile configuration is allowed to change over time.

FIG. 8 illustrates two sets of tile boundaries. Within a CVS, tileboundaries that change position are not allowed to create new partialtiles. FIG. 8 illustrates the invention based on two pictures ofdifferent time instants where the tile boundary of the first set changesposition from time instant T-1 to time instant T and a new tile boundaryof the second set is introduced to keep the position of partial CTUs attime instant T similar to time instant T-1, albeit the occurring changesto scan order, entropy coding and intra prediction.

The seventh aspect of the invention is now described in detail:

In another independent embodiment, the problem is tackled to reduce thecomplexity impact partial CTUs introduce on line buffer requirements.

FIG. 9 illustrates corresponding CTU rows in reference picture afterpartial CTU in current picture.

A horizontal row of partial CTUs in one picture would lead a CTU gridmisalignment with respect to reference picture without the row ofpartial CTUs as illustrated in FIG. 9 where a single row (Current CTUrow) would access to CUs (CU = coding unit) of two CTU rows for toolssuch as ATMVP (Alternative Temporal Motion Vector Prediction). As thecollocated CTU row is often cached in a cost intensive high-speed memoryin hardware implementations (referred to as line buffer), it isundesirable to hold multiple CTU rows in this cache. Therefore, in orderto maintain CTU row alignment across picture in presence of partial CTUcreating tile boundaries, another constraint is that horizontal tileboundaries that create partial CTUs above them are not allowed to changeduring a coded video sequence and are hence static.

In the following, predictors derivation from collocated CTUs accordingto embodiments is described.

In particular, the eighth aspect of the invention is now described indetail:

TMVP (Temporal Motion Vector Prediction) and ATMVP derivation currentlydepends on the pre-defined CTU size, i.e. using a constant CTU grid overthe picture:

For TMVP:

-   If yCb >> CtbLog2SizeY is equal to yColBr >> CtbLog2SizeY, yColBr is    less than pic_height_in_luma_samples and xColBr is less than    pic_width_in_luma_samples-   (in other words: if the bottom-right CB of the reference picture is    in the same CTU row, hence it can be cached in a line buffer memory)

Then the right-bottom collocated predictor is taken. Otherwise (if thebottom-right CB of the reference picture is NOT in the same CTU row,hence it is NOT in the line buffer), the center-collocated predictor istaken.

And for ATMVP:

The location ( xColSb, yColSb ) of the collocated subblock inside ColPicis derived as follows.

-   xColSb = Clip3( xCtb, Min( CurPicWidthInSamplesY - 1, xCtb + ( 1 <<    CtbLog2SizeY) + 3), xSb + ( tempMv[0] >> 4 ) )-   yColSb ₌ Clip3( yCtb, Min( CurPicHeightInSamplesY - 1, yCtb + (1 <<    CtbLog2SizeY) - 1 ), ySb + ( tempMv[1] >> 4))

In other words, coordinates of the collocated sub-blocks are clipped ineach dimension to be inside the same CTU row. The same line bufferconsiderations hold true.

Both TMVP and ATMVP use the size of the pre-defined CTU CtbLog2SizeYthat divides all samples of the coded picture(s) into coded blocks forderivation of the collocated blocks and subblocks.

With tiles borders, that are allowed to create partial CTUs, the CTUgrid is not constant and may vary from picture to picture and createoverlap between a varying number of CTU rows as illustrated in FIG. 9 .In this part of the invention, the CTU grid of the current picture isimposed onto the reference frame to organize buffer management andpredictor access. In other words, the current local partial CTUdimensions or size are applied for selecting the referenced area in theused (collocated) reference picture (as opposed to a constant maximumCTU size across the picture).

For TMVP, one embodiment of the invention is: yTileStart and xTileStartcorrespond to the top-left sample position of a given tile hosting thecurrent coding block with yCblnTile and xCblnTile correspond to thesample position of the current coding block relative to the tile startand collocated blocks correspondingly.

(Differences are highlighted in bold):

-   yCblnTile ₌ yCb-yTileStart-   yColBrlnTile ₌ yColBr-yTileStart-   and CtbLog2HeightY(y) describing the height of the respective CTU    row.

-   If yCblnTile >> CtbLog2HeightY(yCblnTile) is equal to    yColBrinTile >> CtbLog2HeightY(yCblnTile), yColBr is less than    pic_height_in_luma_samples and xColBr is less than    pic_width_in_luma_samples-   then the right-bottom collocated predictor is taken. Otherwise, the    center-collocated predictor is taken.

For ATMVP, an embodiment in form of an adjusted clipping operation is asfollows: The location ( xColSb, yColSb ) of the collocated subblockinside ColPic is derived as follows.

-   xColSb = Clip3( xCtb, Min( CurPicWidthInSamplesY - 1, xCtb + ( 1 <<    CtbLog2WidthY(xCtb)) + 3 ), xSb + ( tempMv[0] >> 4 ) )-   yColSb ₌ Clip3( yCtb, Min( CurPicHeightInSamplesY - 1, yCtb + (1 <<    CtbLog2HeightY(yCtb)) - 1 ), ySb + ( tempMv[1] >> 4))

In the following, sub-picture wise coding tool restriction indication isdescribed. In particular, the ninth aspect of the invention is nowdescribed in detail:

In former video coding standards, sub-picture (e.g. slices or tiles)wise coding restrictions are distinguished as follows:

-   I_SLICE - intra coding, usually random access points, does not use    references to other pictures-   P_SLICE - predictive coding. Use one picture from one reference    picture list for motion compensated prediction.-   B_SLICE - bi-predictive coding with two reference picture lists.    Allows combining motion compensated predictions from pictures in    both lists.

The term slice or tile in this context are interchangeable, i.e. a groupof consecutive-in-bitstream CTUs belonging to a single coded picture andbeing jointly entropy coded.

This differentiation allows two things, namely

-   controlling the parsing and decoding process of the respective    sub-picture right on from slice or tile header parsing, and-   profiling based on such types by for instance prohibiting usage of    computationally complex types such as B_SLICES.

The type indication can also be interpreted as a bag of constraintsassociated with each type, e.g. the I_SLICE type being the mostrestricted type, P_SLICE type relaxing the constraint to includeinter-prediction using one reference picture and B_SLICE type relaxingthe constraint further to include reference from both temporallypreceding and following pictures by allowing a bitstream order ofpictures different from the presentation order

The following problems arise:

-   I_SLICE type can also comprise “current picture referencing”, which    is a P_SLICE type like “motion” compensated or translation    compensated block based prediction using the currently coded picture    as reference-   P_SLICE is not used frequently anymore and mostly replaced by    B_SLICE in applications-   Inter-prediction has evolved beyond usage of two reference frames

Current picture referencing as referred to above imposes additionalcomplexity to the decoding process compared to traditional intraprediction. Traditionally, intra prediction relies only on sample valueswithin the current picture which are in close proximity to the currentlypredicted block, e.g. the directly neighboring samples or, in so calledmulti-reference-line prediction, a small number (e.g. 3) of lines ofdirectly neighboring samples, to generate the sample values of thepredicted block, e.g. through interpolation. Current picture referencingon the other hand relies on mechanisms formerly only used ininter-prediction between frames of a video sequence in which the samplevalues of a reference block are copied to the current block location,the amount of samples accessed to generate the predictor in thistechnique is much higher than regular intra-prediction. For one, thepredictor samples are not only derived from much fewer accessed samplescompared but the search on encoder side to derive a suitable motionvector or displacement information is much higher. Furthermore, thereference picture has to be updated along the decoding process of thecurrent picture to reflect the availability of ever greater regions onthe current picture, i.e. the reconstructed regions, for reference.

In one embodiment of the invention, instead of using the above typedistinction, the actual imposed tool constraints are signaled in the(tile) header.

-   1) A flag should be used to indicate whether the use of reference    picture other than the current picture may be used (intra/inter    switch)-   2) A flag shall be used to indicate the use of current picture    referencing (inter-prediction using the currently coded picture).    This may be signaled depending on the intra/inter selection.-   3) A syntax element is signaled to indicate the number of reference    picture lists that are used in the prediction process. In the case    that current picture referencing only is used, this syntax element    may be inferred to be equal to 1. In other cases the value of 1    refers to what previously was a P_SLICE type, while 2 refers to    former B_SLICE type. Additional values may be used for instance to    indicate multi-hypothesis prediction.

An example syntax could be as follows:

tile_header( ) { Descriptor  [...]  current_picture_only_reference_flagu(1)  current_picture_inter_reference_flag u(1) num_ref_pic_lists_active ue(v)  [...]

current_picture_only_reference_flag equal to 1 indicates that only usingthe current picture as reference is allowed. This is similar toclassical I_SLICE type.

current_picture_inter_reference_flag equal to 1 indicates that thecurrent picture is available for inter prediction (“Current picturereferencing” or “Intra Block Copy” tools).

num_ref_pic_lists_active indicates the number of active referencepictures lists.

If current_picture_only_reference_flag is equal to 1 and

-   current_picture_inter_reference_flag is equal to 0,-   num_ref_pic_lists_active shall be active to zero (and could be    omitted from the bitstream).

If current_picture_only_reference_flag is equal to 0,

-   num_ref_pic_lists_active equal to 1 would indicate a tile type    similar to P_SLICE.-   num_ref_pic_lists_active equal to 2 would indicate a tile type    similar to B_SLICE.-   num_ref_pic_lists_active larger than 2 can be used to indicate the    use of more reference picture lists, e.g. for multi-hypothesis inter    prediction.

In the following, further examples of the invention are provided:

Example 1: A video encoder (101) for encoding a plurality of pictures ofa video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein the data encoder (110) is configured to partition each of    the plurality of pictures such that each picture of the plurality of    pictures comprises a same first number of partial units among the    plurality of coding tree units of the picture,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode the original picture data of    each of the plurality of tiles of the picture independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 2: A video encoder (101) according to example 1,

wherein the data encoder (110) is configured to partition each pictureof the plurality of pictures into the plurality of tiles such that eachtile of the plurality of tiles of each picture of the plurality ofpictures comprises a same second number of partial units among theplurality of coding tree units of the tile.

Example 3: A video encoder (101) according to example 2,

-   wherein the data encoder (110) comprises at least two processors,    and-   wherein the data encoder (110) is configured to encode the original    picture data of a first tile of the plurality of tiles of one of the    plurality of pictures by a first processor of the at least two    processors,-   wherein the data encoder (110) is configured to encode the original    picture data of a second tile of the plurality of tiles of the one    of the plurality of pictures by a second processor of the at least    two processors, and-   wherein the first processor and the second processor are arranged    such that the first processor encodes the original picture data of    the first tile in parallel to the second processor encoding the    original picture data of the second tile.

Example 4: A video encoder (101) according to one of examples 1 to 3,

wherein the data encoder (120) is configured to generate the encodedvideo signal such that the encoded video signal further comprises a flagindicating that each picture of the plurality of pictures comprises thesame first number of partial units among the plurality of coding treeunits of the picture.

Example 5: A video encoder (101) according to one of examples 1 to 4,

wherein, for each picture of the plurality of pictures, the data encoder(110) is configured to partition the picture into the plurality ofcoding tree units, such that each coding tree unit of the plurality ofcoding tree units comprises a number of the samples of the picture beingequal to a predefined sample number or being smaller than the predefinedsample number.

Example 6: A video encoder (101) for encoding a plurality of pictures ofa video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, a    partitioning of the picture defines in a first way, how the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to determine a complexity value    depending on a number of samples of each of the plurality of coding    tree units of each of the plurality of tiles of the picture,-   wherein, if the complexity value is greater than a complexity    threshold value, the data encoder (110) is configured to adapt the    partitioning of the picture and is configured to define in a    different, second way, how the picture is partitioned,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode, depending on the partitioning    of the picture, the original picture data of each of the plurality    of tiles of the picture independently from the original picture data    of any other tile of the plurality of tiles of the picture.

Example 7: A video encoder (110) according to example 6,

-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to determine the complexity value by    determining a CTU-dependent value for each coding tree unit of the    plurality of coding tree units of each of the plurality of tiles of    the picture, wherein the CTU-dependent value of the coding tree unit    depends on whether the coding tree unit is a partial unit or whether    the coding tree unit is a full unit,-   wherein the coding tree unit is a partial unit, if the number of    samples of the coding tree unit is smaller than a predefined sample    number, and-   wherein the coding tree unit is a full unit, if the number of    samples of the coding tree unit is not smaller than the predefined    sample number.

Example 8: A video encoder (110) according to example 7,

wherein a predefined minimum size exists, so that each of the pluralityof coding tree units of each of the plurality of pictures being apartial unit comprises at least the predefined minimum size of theplurality of samples of the picture.

Example 9: A video encoder (110) according to example 8,

wherein each of the plurality of coding tree units of each of theplurality of pictures being a partial unit comprises has a minimumhorizontal sample length and a minimum vertical sample length, wherein anumber of samples of the minimum horizontal sample length is equal to anumber of samples of the minimum vertical sample length.

Example 10: A video encoder (110) according to one of examples 7 to 9,

wherein, for each picture of the plurality of pictures, the data encoder(110) is configured to determine the complexity value by adding theCTU-dependent values of the plurality of coding tree units of theplurality of tiles of the picture.

Example 11: A video encoder (110) according to example 10,

-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value depends on the number of samples    of the coding tree unit, if the coding tree unit is a full unit, and-   such that the CTU-dependent value depends on the number of samples    of the coding tree unit and further depends on a complexity factor,    if the coding tree unit is a partial unit.

Example 12: A video encoder (110) according to example 11,

-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value is the number of samples of the    coding tree unit, if the coding tree unit is a full unit, and-   such that the CTU-dependent value is a product of the complexity    factor times the number of samples of the coding tree unit, if the    coding tree unit is a partial unit, wherein the complexity factor is    a scalar value being different from 0.

Example 13: A video encoder (110) according to example 10,

-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value depends on the number of samples    of the coding tree unit, if the coding tree unit is a full unit, and-   such that the CTU-dependent value is equal to the CTU-dependent    value of another one of the plurality of coding tree units being a    full unit, if the coding tree unit is a partial unit.

Example 14: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of each of the    plurality of tiles of the picture, the coding tree unit is either a    partial unit or a full unit, wherein the coding tree unit is the    partial unit, if the number of samples of the coding tree unit is    smaller than a predefined sample number, and wherein the coding tree    unit is the full unit, if the number of samples of the coding tree    unit is not smaller than the predefined sample number,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode the original picture data of    each of the plurality of tiles of the picture independently from the    original picture data of any other tile of the plurality of tiles of    the picture,-   wherein the data encoder (110) is configured to generate the encoded    video signal such that the encoded video signal further comprises    indication data providing information on a number of the coding tree    units that are partial units among the plurality of coding tree    units of a tile of the plurality of tiles of a picture of the    plurality of pictures.

Example 15: A video encoder (101) according to example 14,

wherein the indication data indicates a maximum number of the codingtree units that are the partial units among the plurality of coding treeunits of the tile.

Example 16: A video encoder (101) according to example 13,

wherein the maximum number of the coding tree units that are the partialunits among the plurality of coding tree units of the tile depends on amaximum tile size.

Example 17: A video encoder (101) according to example 15 or 16,

wherein the maximum number of the coding tree units that are the partialunits among the plurality of coding tree units of the tile depends on afirst number of samples of one of the plurality of coding tree unitswhich is a full unit, the first number being the predefined samplenumber, and further depends on a second number of samples of another oneof the plurality of coding tree units which is a partial unit.

Example 18: A video encoder (101) according to one of examples 14 to 17,

wherein the indication data indicates a relative amount of the codingtree units that are the partial units among the plurality of coding treeunits of the tile.

Example 19: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture,    wherein for each coding tree unit of the plurality of coding tree    units of each of the plurality of tiles of the picture, the coding    tree unit is either a partial unit or a full unit, wherein the    coding tree unit is the partial unit, if the number of samples of    the coding tree unit is smaller than a predefined sample number, and    wherein the coding tree unit is the full unit, if the number of    samples of the coding tree unit is not smaller than the predefined    sample number,-   wherein for at least two pictures of the plurality of pictures, the    data encoder (110) is configured to partition the picture such that    the at least two pictures have a same partial-to-full-unit ratio,    wherein the partial-to-full-unit ratio defines for a picture of the    plurality of pictures a ratio of a number of the coding tree units    of the picture that are partial units to a number of the coding tree    units of the picture that are full units,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode the original picture data of    each of the plurality of tiles of the picture independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 20: A video encoder (101) according to example 19,

wherein for each of the plurality of pictures, the data encoder (110) isconfigured to partition the picture such that each of the plurality ofpictures has the partial-to-full-unit ratio being smaller than athreshold value.

Example 21: A video encoder (101) according to example 19 or 20,

wherein the threshold value is 1.

Example 22: A video encoder (101) according to one of examples 19 to 21,

wherein for each of the plurality of pictures, the data encoder (110) isconfigured to partition the picture such that the plurality of pictureshave the same partial-to-full-unit ratio.

Example 23: A video encoder (101) according to one of examples 1 to 5 oraccording to one of examples 7 to 22, wherein for each tile of theplurality of tiles of each picture of the plurality of pictures, codingtree units of the tile that are partial units appear only at a bottomborder or at a right border of the tile.

Example 24: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture    and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the data encoder (110) is configured to partition the    current picture into the plurality of tiles such that a ratio    between the coding tree units of the current picture being    misaligned to the coding tree units of the current picture being    correctly aligned is not greater than a threshold value,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode the original picture data of    each of the plurality of tiles of the picture independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 25: A video encoder (101) according to example 24,

-   wherein for each coding tree unit of the plurality of coding tree    units of each of the plurality of tiles of the picture, the coding    tree unit is either a partial unit or a full unit, wherein the    coding tree unit is the partial unit, if the number of samples of    the coding tree unit is smaller than a predefined sample number, and    wherein the coding tree unit is the full unit, if the number of    samples of the coding tree unit is not smaller than the predefined    sample number,-   wherein two or more of the plurality of coding tree units being said    full unit and wherein at least one of the plurality of coding tree    units being said partial unit.

Example 26: A video encoder (101) according to example 24 or 25,

wherein the data encoder (110) is configured to receive a bitstreamcomprising the threshold value.

Example 27: A video encoder (101) according to one of examples 24 to 26,

wherein the threshold value is smaller than 1.

Example 28: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture by defining a plurality of tile boundaries for each tile    of the plurality of tiles, wherein each coding tree unit of the    plurality of coding tree units of each picture of the plurality of    pictures comprises a plurality of samples of the picture,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode, depending on the plurality of    tile boundaries of each tile of the plurality of tiles of the    picture, the original picture data of said tile independently from    the original picture data of any other tile of the plurality of    tiles of the picture,-   wherein each tile boundary of the plurality of tile boundaries of    each of the plurality of tiles of each of the plurality of pictures    is either assigned to a first set of tile boundaries or is assigned    to a second set of tile boundaries,-   wherein the data encoder (110) is configured to change an encoding    scan order at a first tile boundary of the plurality of tile    boundaries of a first tile of the plurality of tiles of a picture of    the plurality of pictures, when encoding the original picture data,    if said tile boundary is assigned to the first set of tile    boundaries, and-   wherein the data encoder (110) is configured to not change the    encoding scan order at a second tile boundary of the plurality of    tile boundaries of a second tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 29: A video encoder (101) according to example 28,

-   wherein the data encoder (110) is configured to apply an intra    prediction constraint at a third tile boundary of the plurality of    tile boundaries of a third tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein the data encoder (110) is configured to not apply the intra    prediction constraint at a fourth tile boundary of the plurality of    tile boundaries of a fourth tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 30: A video encoder (101) according to example 29,

-   wherein the data encoder (110) is configured to conduct an entropy    coding reset constraint at a fifth tile boundary of the plurality of    tile boundaries of a fifth tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein the data encoder (110) is configured to not conduct the    entropy coding reset at a sixth tile boundary of the plurality of    tile boundaries of a sixth tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 31: A video encoder (101) according to one of examples 28 to 30,

-   wherein each coding tree unit of the plurality of coding tree units    of each picture of the plurality of pictures has a position within    the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the data encoder (110) is configured to partition the    current picture into the plurality of tiles such that more than half    of the coding tree units of the current picture are correctly    aligned, and such that less than half of the coding tree units of    the current picture are misaligned.

Example 32: A video encoder (101) according to example 31,

wherein, for each picture of the one or more subsequent pictures, thedata encoder (110) is configured to partition the picture into theplurality of tiles such that all of the coding tree units of the pictureare correctly aligned, and such that none of the coding tree units ofthe picture are misaligned.

Example 33: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture    and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the plurality of coding tree units of the current picture is    arranged within the current picture such that the plurality of    coding tree units of the current picture form one or more rows of    coding tree units of the current picture,-   wherein the data encoder (110) is configured to partition the    current picture such that there exists no row among the one or more    rows of the current picture where any coding tree unit of said row    is misaligned,-   wherein the data encoder (110) is configured to encode the original    picture data of each of the plurality of tiles of the current    picture independently from the original picture data of any other    tile of the plurality of tiles of the current picture.

Example 34: A video encoder (101) according to example 33,

wherein the data encoder (110) is configured to generate the encodedvideo signal such that the encoded video signal comprises an indicationthat no row among the one or more rows of the picture exists, where anycoding tree unit of said row is misaligned.

Example 35: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture    and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture, wherein the reference picture precedes the    current picture in time,-   wherein the data encoder (110) is configured to determine a motion    vector of the current picture depending on a motion vector of the    reference picture and depending on how the current picture is    partitioned, and-   wherein the data encoder (110) is configured to encode, depending on    the motion vector of the current picture, the original picture data    of each of the plurality of tiles of the current picture    independently from the original picture data of any other tile of    the plurality of tiles of the picture.

Example 36: A video encoder (101) according to example 35,

wherein the data encoder (110) is configured to determine the motionvector of the current picture by selecting a first motion vectorpredictor at a first location within the reference picture or a secondmotion vector predictor at a second location within the referencepicture depending on a location of the motion vector of the currentpicture and depending on how the current picture is partitioned.

Example 37: A video encoder (101) according to example 36,

-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture, and-   wherein at least two coding tree units of the plurality of coding    tree units of the current picture are misaligned.

Example 38: A video encoder (101) according to example 35,

-   wherein the data encoder (110) is configured to determine a motion    vector of the current picture    -   by determining a position of a related block in the reference        picture depending on how the current picture is partitioned,    -   by determining a location of a motion vector predictor in the        reference picture depending on a location of the motion vector        in the current block, and    -   by applying a clipping operation on the location of the motion        vector predictor in the reference picture to adapt the location        of the motion vector predictor in the reference picture        depending on how the current picture is partitioned.

Example 39: A video encoder (101) according to one of examples 24 to 38,

-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein for each tile of the plurality of tiles of each picture of    the plurality of pictures, coding tree units of the tile that are    partial units appear only at a bottom border or at a right border of    the tile.

Example 40: A video encoder (101) for encoding a plurality of picturesof a video by generating an encoded video signal, wherein each of theplurality of pictures comprises original picture data, wherein the videoencoder (101) comprises:

-   a data encoder (110) configured for generating the encoded video    signal comprising encoded picture data, wherein the data encoder is    configured to encode the plurality of pictures of the video into the    encoded picture data, and-   an output interface (120) configured for outputting the encoded    picture data of each of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to partition the picture into a    plurality of tiles comprising a plurality of coding tree units of    the picture, wherein each coding tree unit of the plurality of    coding tree units comprises a plurality of samples of the picture,-   wherein, for each picture of the plurality of pictures, the data    encoder (110) is configured to encode the original picture data of    each of the plurality of tiles of the picture,-   wherein the data encoder (110) is configured to generate the encoded    video signal such that the encoded video signal further comprises a    first flag that indicates for a current picture of the plurality of    pictures, whether a reference picture of the plurality of pictures    being different from the current picture has been used for encoding    the current picture.

Example 41: A video encoder (101) according to example 40,

wherein the data encoder (110) is configured to generate the encodedvideo signal such that the encoded video signal further comprises asecond flag that indicates whether current picture referencing is used,wherein using the current picture referencing comprises copying areference block of a picture of the plurality of pictures to a currentblock of said picture, being different from the reference block.

Example 42: A video encoder (101) according to example 40 or 41,

wherein the data encoder (110) is configured to generate the encodedvideo signal such that the encoded video signal further comprises asyntax element that indicates a number of reference picture lists thatare used in prediction.

Example 43: A video encoder (101) according to example 42,

wherein the data encoder (110) is configured to set the syntax elementthat indicates the number of the reference picture lists that are usedin prediction to a value 0 or to a value 1 or to a value 2, but not to adifferent value.

Example 44: A video encoder (101) according to example 42,

wherein the data encoder (110) is configured to set the syntax elementthat indicates the number of the reference picture lists that are usedin prediction to a value 0 or to a value 1 or to a value 2 or to aninteger value being greater than 2.

Example 45: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein each of the plurality of pictures is partitioned such that    each picture of the plurality of pictures comprises a same first    number of partial units among the plurality of coding tree units of    the picture,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode the encoded picture data of    each of the plurality of tiles of the picture independently from the    encoded picture data of any other tile of the plurality of tiles of    the picture.

Example 46: A video decoder (151) according to example 45,

wherein each picture of the plurality of pictures is partitioned intothe plurality of tiles such that each tile of the plurality of tiles ofeach picture of the plurality of pictures comprises a same second numberof partial units among the plurality of coding tree units of the tile.

Example 47: A video decoder (151) according to example 46,

-   wherein the data decoder (170) comprises at least two processors,    and-   wherein the data decoder (170) is configured to decode the encoded    picture data of a first tile of the plurality of tiles of one of the    plurality of pictures by a first processor of the at least two    processors,-   wherein the data decoder (170) is configured to decode the encoded    picture data of a second tile of the plurality of tiles of the one    of the plurality of pictures by a second processor of the at least    two processors, and-   wherein the first processor and the second processor are arranged    such that the first processor decodes the encoded picture data of    the first tile in parallel to the second processor decoding the    encoded picture data of the second tile.

Example 48: A video decoder (151) according to one of examples 45 to 47,

-   wherein the encoded video signal further comprises a flag indicating    that each picture of the plurality of pictures comprises the same    first number of partial units among the plurality of coding tree    units of the picture,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode the encoded picture data of    each of the plurality of tiles of the picture depending on the flag,    independently from the encoded picture data of any other tile of the    plurality of tiles of the picture.

Example 49: A video decoder (151) according to one of examples 45 to 48,

wherein, for each picture of the plurality of pictures, the picture ispartitioned into the plurality of coding tree units, such that eachcoding tree unit of the plurality of coding tree units comprises anumber of the samples of the picture being equal to a predefined samplenumber or being smaller than the predefined sample number.

Example 50: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, the data    decoder (110) is configured to determine a complexity value    depending on a number of samples of each of the plurality of coding    tree units of each of the plurality of tiles of the picture, and-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode depending on the complexity    value the encoded picture data of each of the plurality of tiles of    the picture independently from the encoded picture data of any other    tile of the plurality of tiles of the picture to obtain original    picture data of the plurality of coding tree units of each of the    plurality of pictures.

Example 51: A video decoder (151) according to example 50,

-   wherein, for each picture of the plurality of pictures, data decoder    (170) is configured to determine the complexity value by determining    a CTU-dependent value for each coding tree unit of the plurality of    coding tree units of each of the plurality of tiles of the picture,    wherein the CTU-dependent value of the coding tree unit depends on    whether the coding tree unit is a partial unit or whether the coding    tree unit is a full unit,-   wherein the coding tree unit is a partial unit, if the number of    samples of the coding tree unit is smaller than a predefined sample    number, and-   wherein the coding tree unit is a full unit, if the number of    samples of the coding tree unit is not smaller than the predefined    sample number.

Example 52: A video decoder (151) according to example 51,

wherein a predefined minimum size exists, so that each of the pluralityof coding tree units of each of the plurality of pictures being apartial unit comprises at least the predefined minimum size of theplurality of samples of the picture.

Example 53: A video decoder (151) according to example 52,

wherein each of the plurality of coding tree units of each of theplurality of pictures being a partial unit comprises has a minimumhorizontal sample length and a minimum vertical sample length, wherein anumber of samples of the minimum horizontal sample length is equal to anumber of samples of the minimum vertical sample length.

Example 54: A video decoder (151) according to one of examples 51 to 53,

wherein, for each picture of the plurality of pictures, the data decoder(170) is configured to determine the complexity value by adding theCTU-dependent values of the plurality of coding tree units of theplurality of tiles of the picture.

Example 55: A video decoder (151) according to example 54,

-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value depends on the number of samples    of the coding tree unit, if the coding tree unit is a full unit, and-   such that the CTU-dependent value depends on the number of samples    of the coding tree unit and further depends on a complexity factor,    if the coding tree unit is a partial unit.

Example 56: A video decoder (151) according to example 55,

-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value is the number of samples of the    coding tree unit, if the coding tree unit is a full unit, and-   such that the CTU-dependent value is a product of the complexity    factor times the number of samples of the coding tree unit, if the    coding tree unit is a partial unit, wherein the complexity factor is    a scalar value being different from 0.

Example 57: A video decoder (151) according to example 51,

-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to determine the CTU-dependent value for    each coding tree unit of the plurality of coding tree units of each    of the plurality of tiles of the picture,-   such that the CTU-dependent value of the coding tree unit depends on    the number of samples of the coding tree unit, if the coding tree    unit is a full unit, and-   such that the CTU-dependent value of the coding tree unit is equal    to the CTU-dependent value of another one of the plurality of coding    tree units being a full unit, if the coding tree unit is a partial    unit.

Example 58: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of each of the    plurality of tiles of the picture, the coding tree unit is either a    partial unit or a full unit, wherein the coding tree unit is the    partial unit, if the number of samples of the coding tree unit is    smaller than a predefined sample number, and wherein the coding tree    unit is the full unit, if the number of samples of the coding tree    unit is not smaller than the predefined sample number,-   wherein the encoded video signal further comprises indication data    providing information on a number of the coding tree units that are    partial units among the plurality of coding tree units of a tile of    the plurality of tiles of a picture of the plurality of pictures,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode depending on the indication    data the encoded picture data of each of the plurality of tiles of    the picture independently from the encoded picture data of any other    tile of the plurality of tiles of the picture to obtain original    picture data of the plurality of coding tree units of each of the    plurality of pictures.

Example 59: A video decoder (151) according to example 58,

wherein the indication data indicates a maximum number of the codingtree units that are the partial units among the plurality of coding treeunits of the tile.

Example 60: A video decoder (151) according to example 59,

wherein the maximum number of the coding tree units that are the partialunits among the plurality of coding tree units of the tile depends on amaximum tile size.

Example 61: A video decoder (151) according to example 59 or 60,

wherein the maximum number of the coding tree units that are the partialunits among the plurality of coding tree units of the tile depends on afirst number of samples of one of the plurality of coding tree unitswhich is a full unit, the first number being the predefined samplenumber, and further depends on a second number of samples of another oneof the plurality of coding tree units which is a partial unit.

Example 62: A video decoder (151) according to one of examples 58 to 61,

wherein the indication data indicates a relative amount of the codingtree units that are the partial units among the plurality of coding treeunits of the tile.

Example 63: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture, wherein for each coding tree unit of the plurality    of coding tree units of each of the plurality of tiles of the    picture, the coding tree unit is either a partial unit or a full    unit, wherein the coding tree unit is the partial unit, if the    number of samples of the coding tree unit is smaller than a    predefined sample number, and wherein the coding tree unit is the    full unit, if the number of samples of the coding tree unit is not    smaller than the predefined sample number,-   wherein for at least two pictures of the plurality of pictures, the    picture is partitioned such that the at least two pictures have a    same partial-to-full-unit ratio, wherein the partial-to-full-unit    ratio defines for a picture of the plurality of pictures a ratio of    a number of the coding tree units of the picture that are partial    units to a number of the coding tree units of the picture that are    full units,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode the encoded picture data of    each of the plurality of tiles of the picture independently from the    encoded picture data of any other tile of the plurality of tiles of    the picture to obtain original picture data of the plurality of    coding tree units of each of the plurality of pictures.

Example 64: A video decoder (151) according to example 63,

wherein for each of the plurality of pictures, the picture ispartitioned such that each of the plurality of pictures has thepartial-to-full-unit ratio being smaller than a threshold value.

Example 65: A video decoder (151) according to example 64,

wherein the threshold value is 1.

Example 66: A video decoder (151) according to one of examples 63 to 65,

wherein for each of the plurality of pictures, the picture ispartitioned such that the plurality of pictures have the samepartial-to-full-unit ratio.

Example 67: A video decoder (151) according to one of examples 45 to 49or according to one of examples 51 to 66, wherein for each tile of theplurality of tiles of each picture of the plurality of pictures, codingtree units of the tile that are partial units appear only at a bottomborder or at a right border of the tile.

Example 68: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the current picture is partitioned into the plurality of    tiles such that a ratio between the coding tree units of the current    picture being misaligned to the coding tree units of the current    picture being correctly aligned is not greater than a threshold    value,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode the encoded picture data of    each of the plurality of tiles of the picture independently from the    encoded picture data of any other tile of the plurality of tiles of    the picture to obtain original picture data of the plurality of    coding tree units of each of the plurality of pictures.

Example 69: A video decoder (151) according to example 68,

-   wherein for each coding tree unit of the plurality of coding tree    units of each of the plurality of tiles of the picture, the coding    tree unit is either a partial unit or a full unit, wherein the    coding tree unit is the partial unit, if the number of samples of    the coding tree unit is smaller than a predefined sample number, and    wherein the coding tree unit is the full unit, if the number of    samples of the coding tree unit is not smaller than the predefined    sample number,-   wherein two or more of the plurality of coding tree units being said    full unit and wherein at least one of the plurality of coding tree    units being said partial unit.

Example 70: A video decoder (151) according to example 68 or 69,

wherein the data decoder (170) is configured to receive a bitstreamcomprising the threshold value.

Example 71: A video decoder (151) according to one of examples 68 to 70,

wherein the threshold value is smaller than 1.

Example 72: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture by defining a plurality of tile    boundaries for each tile of the plurality of tiles, wherein each    coding tree unit of the plurality of coding tree units of each    picture of the plurality of pictures comprises a plurality of    samples of the picture,-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode, depending on the plurality of    tile boundaries of each tile of the plurality of tiles of the    picture, the encoded picture data of said tile independently from    the encoded picture data of any other tile of the plurality of tiles    of the picture to obtain original picture data of the plurality of    coding tree units of each of the plurality of pictures,-   wherein each tile boundary of the plurality of tile boundaries of    each of the plurality of tiles of each of the plurality of pictures    is either assigned to a first set of tile boundaries or is assigned    to a second set of tile boundaries,-   wherein the data decoder (170) is configured to change a decoding    scan order at a first tile boundary of the plurality of tile    boundaries of a first tile of the plurality of tiles of a picture of    the plurality of pictures, when decoding the encoded picture data,    if said tile boundary is assigned to the first set of tile    boundaries, and-   wherein the data decoder (170) is configured to not change the    decoding scan order at a second tile boundary of the plurality of    tile boundaries of a second tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 73: A video decoder (151) according to example 72,

-   wherein the data decoder (170) is configured to apply an intra    prediction constraint at a third tile boundary of the plurality of    tile boundaries of a third tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein the data decoder (170) is configured to not apply the intra    prediction constraint at a fourth tile boundary of the plurality of    tile boundaries of a fourth tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 74: A video decoder (151) according to example 73,

-   wherein the data decoder (170) is configured to conduct an entropy    coding reset constraint at a fifth tile boundary of the plurality of    tile boundaries of a fifth tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein the data decoder (170) is configured to not conduct the    entropy coding reset at a sixth tile boundary of the plurality of    tile boundaries of a sixth tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 75: A video decoder (151) according to one of examples 72 to 74,

-   wherein each coding tree unit of the plurality of coding tree units    of each picture of the plurality of pictures has a position within    the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the current picture is partitioned into the plurality of    tiles such that more than half of the coding tree units of the    current picture are correctly aligned, and such that less than half    of the coding tree units of the current picture are misaligned.

Example 76: A video decoder (151) according to example 75,

wherein, for each picture of the one or more subsequent pictures, thepicture is partitioned into the plurality of tiles such that all of thecoding tree units of the picture are correctly aligned, and such thatnone of the coding tree units of the picture are misaligned.

Example 77: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the plurality of coding tree units of the current picture is    arranged within the current picture such that the plurality of    coding tree units of the current picture form one or more rows of    coding tree units of the current picture,-   wherein the current picture is partitioned such that there exists no    row among the one or more rows of the current picture where any    coding tree unit of said row is misaligned,-   wherein the data decoder (170) is configured to decode the encoded    picture data of each of the plurality of tiles of the current    picture independently from the encoded picture data of any other    tile of the plurality of tiles of the current picture to obtain    original picture data of the plurality of coding tree units of the    current picture.

Example 78: A video decoder (151) according to example 77,

-   wherein the data decoder (170) is configured to receive the encoded    video signal comprising an indication that no row among the one or    more rows of the picture exists, where any coding tree unit of said    row is misaligned,-   wherein the data decoder (170) is configured to decode the encoded    picture data of each of the plurality of tiles of the current    picture depending on the indication independently from the encoded    picture data of any other tile of the plurality of tiles of the    current picture to obtain original picture data of the plurality of    coding tree units of the current picture.

Example 79: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture, wherein the reference picture precedes the    current picture in time,-   wherein the data decoder (170) is configured to determine a motion    vector of the current picture depending on a motion vector of the    reference picture and depending on how the current picture is    partitioned into the plurality of tiles of the current picture, and-   wherein, for each picture of the plurality of pictures, the data    decoder (170) is configured to decode, depending on the motion    vector of the current picture, the encoded picture data of each of    the plurality of tiles of the picture independently from the encoded    picture data of any other tile of the plurality of tiles of the    picture to obtain original picture data of the plurality of coding    tree units of each of the plurality of pictures.

Example 80: A video decoder (151) according to example 79,

wherein the data decoder (170) is configured to determine the motionvector of the current picture by selecting a first motion vectorpredictor at a first location within the reference picture or a secondmotion vector predictor at a second location within the referencepicture depending on a location of the motion vector of the currentpicture and depending on how the current picture is partitioned.

Example 81: A video decoder (151) according to example 80,

-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture, and-   wherein at least two coding tree units of the plurality of coding    tree units of the current picture are misaligned.

Example 82: A video decoder (151) according to example 79,

-   wherein the data decoder (170) is configured to determine a motion    vector of the current picture    -   by determining a position of a related block in the reference        picture depending on how the current picture is partitioned,    -   by determining a location of a motion vector predictor in the        reference picture depending on a location of the motion vector        in the current block, and    -   by applying a clipping operation on the location of the motion        vector predictor in the reference picture to adapt the location        of the motion vector predictor in the reference picture        depending on how the current picture is partitioned.

Example 83: A video decoder (151) according to one of examples 68 to 82,

-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein for each tile of the plurality of tiles of each picture of    the plurality of pictures, coding tree units of the tile that are    partial units appear only at a bottom border or at a right border of    the tile.

Example 84: A video decoder (151) for decoding an encoded video signalcomprising encoded picture data to reconstruct a plurality of picturesof a video, wherein the video decoder (151) comprises:

-   an input interface (160) configured for receiving the encoded video    signal, and-   a data decoder (170) configured for reconstructing the plurality of    pictures of the video by decoding the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein the encoded video signal further comprises a first flag that    indicates for a current picture of the plurality of pictures,    whether a reference picture of the plurality of pictures being    different from the current picture has been used for encoding the    current picture,-   wherein, for a picture of the plurality of pictures, the data    decoder (170) is configured to decode the encoded picture data of    each of the plurality of tiles of the picture depending on the first    flag to obtain original picture data of the plurality of coding tree    units of each of the plurality of pictures.

Example 85: A video decoder (151) according to example 84,

-   wherein the encoded video signal further comprises a second flag    that indicates whether current picture referencing is used, wherein    using the current picture referencing comprises copying a reference    block of a picture of the plurality of pictures to a current block    of said picture, being different from the reference block,-   wherein the data decoder (170) is configured to decode the encoded    picture data of each of the plurality of tiles of said picture    depending on the second flag.

Example 86: A video decoder (151) according to example 84 or 85,

-   wherein the encoded video signal further comprises a syntax element    that indicates a number of reference picture lists that are used in    prediction,-   wherein the data decoder (170) is configured to decode the encoded    picture data of each of the plurality of tiles of said picture    depending on the syntax element.

Example 87: A video decoder (151) according to example 86,

wherein the syntax element that indicates the number of the referencepicture lists that are used in prediction is set to a value 0 or to avalue 1 or to a value 2, but not to a different value.

Example 88: A video decoder (151) according to example 86,

wherein the syntax element that indicates the number of the referencepicture lists that are used in prediction is set to a value 0 or to avalue 1 or to a value 2 or to an integer value being greater than 2.

Example 89: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein partitioning each of the plurality of pictures is conducted    such that each picture of the plurality of pictures comprises a same    first number of partial units among the plurality of coding tree    units of the picture,-   wherein, for each picture of the plurality of pictures, encoding the    original picture data of each of the plurality of tiles of the    picture is conducted independently from the original picture data of    any other tile of the plurality of tiles of the picture.

Example 90: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein each of the plurality of pictures is partitioned such that    each picture of the plurality of pictures comprises a same first    number of partial units among the plurality of coding tree units of    the picture,-   wherein, for each picture of the plurality of pictures, decoding the    encoded picture data of each of the plurality of tiles of the    picture is conducted independently from the encoded picture data of    any other tile of the plurality of tiles of the picture.

Example 91: A computer program for implementing the method of example 89or 90 when being executed on a computer or signal processor.

Example 92: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of the picture is    either a partial unit or a full unit, wherein the coding tree unit    is the partial unit, if the number of samples of the coding tree    unit is smaller than a predefined sample number, and wherein the    coding tree unit is the full unit, if the number of samples of the    coding tree unit is not smaller than the predefined sample number,-   wherein partitioning each of the plurality of pictures is conducted    such that each picture of the plurality of pictures comprises a same    first number of partial units among the plurality of coding tree    units of the picture,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded within the encoded video signal independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 93: A system comprising:

-   the video encoder (101) according to one of examples 1 to 5, and-   the video decoder (151) according to one of examples 45 to 49,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 94: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein, for each picture of the plurality of pictures, a    partitioning of the picture defines in a first way, how the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein the method further comprises    -   for each picture of the plurality of pictures, determine a        complexity value depending on a number of samples of each of the        plurality of coding tree units of each of the plurality of tiles        of the picture,    -   if the complexity value is greater than a complexity threshold        value, adapting the partitioning of the picture and is        configured to define in a different, second way, how the picture        is partitioned,    -   wherein, for each picture of the plurality of pictures,        encoding, depending on the partitioning of the picture, the        original picture data of each of the plurality of tiles of the        picture independently from the original picture data of any        other tile of the plurality of tiles of the picture.

Example 95: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   for each picture of the plurality of pictures, the picture is    partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, determining a        complexity value depending on a number of samples of each of the        plurality of coding tree units of each of the plurality of tiles        of the picture, and    -   for each picture of the plurality of pictures, decoding        depending on the complexity value the encoded picture data of        each of the plurality of tiles of the picture independently from        the encoded picture data of any other tile of the plurality of        tiles of the picture to obtain original picture data of the        plurality of coding tree units of each of the plurality of        pictures.

Example 96: A computer program for implementing the method of example 94or 95 when being executed on a computer or signal processor.

Example 97: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein the partitioning of the picture depends on whether a    complexity value is greater than a complexity threshold value,    wherein the complexity value depends on a number of samples of each    of the plurality of coding tree units of each of the plurality of    tiles of the picture,-   wherein, for each picture of the plurality of pictures, original    picture data of each of the plurality of tiles of the picture is    encoded within the encoded video signal independently from original    picture data of any other tile of the plurality of tiles of the    picture.

Example 98: A system comprising:

-   the video encoder (101) according to one of examples 6 to 13, and-   the video decoder (151) according to one of examples 50 to 57,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 99: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of each of the    plurality of tiles of the picture, the coding tree unit is either a    partial unit or a full unit, wherein the coding tree unit is the    partial unit, if the number of samples of the coding tree unit is    smaller than a predefined sample number, and wherein the coding tree    unit is the full unit, if the number of samples of the coding tree    unit is not smaller than the predefined sample number,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, encoding the        original picture data of each of the plurality of tiles of the        picture independently from the original picture data of any        other tile of the plurality of tiles of the picture,-   wherein generating the encoded video signal is conducted such that    the encoded video signal further comprises indication data providing    information on a number of the coding tree units that are partial    units among the plurality of coding tree units of a tile of the    plurality of tiles of a picture of the plurality of pictures.

Example 100: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of each of the    plurality of tiles of the picture, the coding tree unit is either a    partial unit or a full unit, wherein the coding tree unit is the    partial unit, if the number of samples of the coding tree unit is    smaller than a predefined sample number, and wherein the coding tree    unit is the full unit, if the number of samples of the coding tree    unit is not smaller than the predefined sample number,-   wherein the encoded video signal further comprises indication data    providing information on a number of the coding tree units that are    partial units among the plurality of coding tree units of a tile of    the plurality of tiles of a picture of the plurality of pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, decoding        depending on the indication data the encoded picture data of        each of the plurality of tiles of the picture independently from        the encoded picture data of any other tile of the plurality of        tiles of the picture to obtain original picture data of the        plurality of coding tree units of each of the plurality of        pictures.

Example 101: A computer program for implementing the method of example99 or 100 when being executed on a computer or signal processor.

Example 102: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, each coding    tree unit of the plurality of coding tree units of each of the    plurality of tiles of the picture, the coding tree unit is either a    partial unit or a full unit, wherein the coding tree unit is the    partial unit, if the number of samples of the coding tree unit is    smaller than a predefined sample number, and wherein the coding tree    unit is the full unit, if the number of samples of the coding tree    unit is not smaller than the predefined sample number,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded independently from the original picture data of any other    tile of the plurality of tiles of the picture within the encoded    video signal,-   wherein the encoded video signal further comprises indication data    providing information on a number of the coding tree units that are    partial units among the plurality of coding tree units of a tile of    the plurality of tiles of a picture of the plurality of pictures.

Example 103: A system comprising:

-   the video encoder (101) according to one of examples 14 to 18, and-   the video decoder (151) according to one of examples 58 to 62,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 104: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture, wherein for each coding tree unit of the        plurality of coding tree units of each of the plurality of tiles        of the picture, the coding tree unit is either a partial unit or        a full unit, wherein the coding tree unit is the partial unit,        if the number of samples of the coding tree unit is smaller than        a predefined sample number, and wherein the coding tree unit is        the full unit, if the number of samples of the coding tree unit        is not smaller than the predefined sample number,    -   wherein for at least two pictures of the plurality of pictures,        partitioning the picture is conducted such that the at least two        pictures have a same partial-to-full-unit ratio, wherein the        partial-to-full-unit ratio defines for a picture of the        plurality of pictures a ratio of a number of the coding tree        units of the picture that are partial units to a number of the        coding tree units of the picture that are full units,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded independently from the original picture data of any other    tile of the plurality of tiles of the picture.

Example 105: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture, wherein for each coding tree unit of the plurality    of coding tree units of each of the plurality of tiles of the    picture, the coding tree unit is either a partial unit or a full    unit, wherein the coding tree unit is the partial unit, if the    number of samples of the coding tree unit is smaller than a    predefined sample number, and wherein the coding tree unit is the    full unit, if the number of samples of the coding tree unit is not    smaller than the predefined sample number,-   wherein for at least two pictures of the plurality of pictures, the    picture is partitioned such that the at least two pictures have a    same partial-to-full-unit ratio, wherein the partial-to-full-unit    ratio defines for a picture of the plurality of pictures a ratio of    a number of the coding tree units of the picture that are partial    units to a number of the coding tree units of the picture that are    full units,-   wherein, for each picture of the plurality of pictures, decoding the    encoded picture data of each of the plurality of tiles of the    picture is conducted independently from the encoded picture data of    any other tile of the plurality of tiles of the picture to obtain    original picture data of the plurality of coding tree units of each    of the plurality of pictures.

Example 106: A computer program for implementing the method of example104 or 105 when being executed on a computer or signal processor.

Example 107: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture, wherein for each coding tree unit of the plurality    of coding tree units of each of the plurality of tiles of the    picture, the coding tree unit is either a partial unit or a full    unit, wherein the coding tree unit is the partial unit, if the    number of samples of the coding tree unit is smaller than a    predefined sample number, and wherein the coding tree unit is the    full unit, if the number of samples of the coding tree unit is not    smaller than the predefined sample number,-   wherein for at least two pictures of the plurality of pictures, the    picture is partitioned such that the at least two pictures have a    same partial-to-full-unit ratio, wherein the partial-to-full-unit    ratio defines for a picture of the plurality of pictures a ratio of    a number of the coding tree units of the picture that are partial    units to a number of the coding tree units of the picture that are    full units,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded within the encoded video signal independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 108: A system comprising:

-   the video encoder (101) according to one of examples 19 to 22, and-   the video decoder (151) according to one of examples 63 to 66,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 109: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein partitioning the current picture into the plurality of tiles    is conducted such that a ratio between the coding tree units of the    current picture being misaligned to the coding tree units of the    current picture being correctly aligned is not greater than a    threshold value,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded independently from the original picture data of any other    tile of the plurality of tiles of the picture.

Example 110: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the current picture is partitioned into the plurality of    tiles such that a ratio between the coding tree units of the current    picture being misaligned to the coding tree units of the current    picture being correctly aligned is not greater than a threshold    value,-   wherein, for each picture of the plurality of pictures, the encoded    picture data of each of the plurality of tiles of the picture is    decoded independently from the encoded picture data of any other    tile of the plurality of tiles of the picture to obtain original    picture data of the plurality of coding tree units of each of the    plurality of pictures.

Example 111: A computer program for implementing the method of example109 or 110 when being executed on a computer or signal processor.

Example 112: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the current picture is partitioned into the plurality of    tiles is conducted such that a ratio between the coding tree units    of the current picture being misaligned to the coding tree units of    the current picture being correctly aligned is not greater than a    threshold value,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded within the encoded video signal independently from the    original picture data of any other tile of the plurality of tiles of    the picture.

Example 113: A system comprising:

-   the video encoder (101) according to one of examples 24 to 27, and-   the video decoder (151) according to one of examples 68 to 71,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 114: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture by defining a plurality of tile        boundaries for each tile of the plurality of tiles, wherein each        coding tree unit of the plurality of coding tree units of each        picture of the plurality of pictures comprises a plurality of        samples of the picture,    -   for each picture of the plurality of pictures, encoding,        depending on the plurality of tile boundaries of each tile of        the plurality of tiles of the picture, the original picture data        of said tile independently from the original picture data of any        other tile of the plurality of tiles of the picture,-   wherein each tile boundary of the plurality of tile boundaries of    each of the plurality of tiles of each of the plurality of pictures    is either assigned to a first set of tile boundaries or is assigned    to a second set of tile boundaries,-   wherein encoding the original picture data comprises changing an    encoding scan order at a first tile boundary of the plurality of    tile boundaries of a first tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein encoding the original picture data comprises not changing    the encoding scan order at a second tile boundary of the plurality    of tile boundaries of a second tile of the plurality of tiles of a    picture of the plurality of pictures, when encoding the original    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 115: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture by defining a plurality of tile    boundaries for each tile of the plurality of tiles, wherein each    coding tree unit of the plurality of coding tree units of each    picture of the plurality of pictures comprises a plurality of    samples of the picture,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, decoding,        depending on the plurality of tile boundaries of each tile of        the plurality of tiles of the picture, the encoded picture data        of said tile independently from the encoded picture data of any        other tile of the plurality of tiles of the picture to obtain        original picture data of the plurality of coding tree units of        each of the plurality of pictures,-   wherein each tile boundary of the plurality of tile boundaries of    each of the plurality of tiles of each of the plurality of pictures    is either assigned to a first set of tile boundaries or is assigned    to a second set of tile boundaries,-   wherein decoding the encoded picture data comprises changing a    decoding scan order at a first tile boundary of the plurality of    tile boundaries of a first tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the first set of    tile boundaries, and-   wherein decoding the encoded picture data comprises not changing the    decoding scan order at a second tile boundary of the plurality of    tile boundaries of a second tile of the plurality of tiles of a    picture of the plurality of pictures, when decoding the encoded    picture data, if said tile boundary is assigned to the second set of    tile boundaries.

Example 116: A computer program for implementing the method of example114 or 115 when being executed on a computer or signal processor.

Example 117: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture by defining a plurality of tile    boundaries for each tile of the plurality of tiles, wherein each    coding tree unit of the plurality of coding tree units of each    picture of the plurality of pictures comprises a plurality of    samples of the picture,-   wherein, for each picture of the plurality of pictures, the original    picture data of each tile of the plurality of tiles of the picture    is encoded within the encoded video signal, depending on the    plurality of tile boundaries of said tile, independently from the    original picture data of any other tile of the plurality of tiles of    the picture,-   wherein each tile boundary of the plurality of tile boundaries of    each of the plurality of tiles of each of the plurality of pictures    is either assigned to a first set of tile boundaries or is assigned    to a second set of tile boundaries,-   wherein the original picture data is encoded depending on that a    change of an encoding scan order has been conducted at a first tile    boundary of the plurality of tile boundaries of a first tile of the    plurality of tiles of a picture of the plurality of pictures, when    the original picture data has been encoded, if said tile boundary is    assigned to the first set of tile boundaries, and-   wherein the original picture data is encoded depending on that a    change of the encoding scan order has not been conducted at a second    tile boundary of the plurality of tile boundaries of a second tile    of the plurality of tiles of a picture of the plurality of pictures,    when the original picture data has been encoded, if said tile    boundary is assigned to the second set of tile boundaries.

Example 118: A system comprising:

-   the video encoder (101) according to one of examples 28 to 32, and-   the video decoder (151) according to one of examples 72 to 76,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 119: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the plurality of coding tree units of the current picture is    arranged within the current picture such that the plurality of    coding tree units of the current picture form one or more rows of    coding tree units of the current picture,-   wherein partitioning the current picture is conducted such that    there exists no row among the one or more rows of the picture where    any coding tree unit of said row is misaligned,-   wherein encoding the original picture data of each of the plurality    of tiles of the current picture is conducted independently from the    original picture data of any other tile of the current picture.

Example 120: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the plurality of coding tree units of the current picture is    arranged within the current picture such that the plurality of    coding tree units of the current picture form one or more rows of    coding tree units of the current picture,-   wherein the data encoder (110) is configured to partition the    current picture such that there exists no row among the one or more    rows of the current picture where any coding tree unit of said row    is misaligned,-   wherein the data encoder (110) is configured to encode the original    picture data of each of the plurality of tiles of the current    picture independently from the original picture data of any other    tile of the plurality of tiles of the current picture,-   wherein the current picture is partitioned such that there exists no    row among the one or more rows of the current picture where any    coding tree unit of said row is misaligned,-   wherein decoding the encoded picture data of each of the plurality    of tiles of the current picture is conducted independently from the    encoded picture data of any other tile of the plurality of tiles of    the current picture to obtain original picture data of the current    picture.

Example 121: A computer program for implementing the method of example119 or 120 when being executed on a computer or signal processor.

Example 122: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is correctly aligned, if    another coding tree unit among the plurality of coding tree units of    the reference picture exists, the position of said another coding    tree unit within the reference picture being equal to the position    of said coding tree unit within the current picture,-   wherein for each coding tree unit of the coding tree units of the    current picture, the coding tree unit is misaligned, if no other    coding tree unit among the plurality of coding tree units of the    reference picture exists, having a position within the reference    picture being equal to the position of said coding tree unit within    the current picture,-   wherein the plurality of coding tree units of the current picture is    arranged within the current picture such that the plurality of    coding tree units of the current picture form one or more rows of    coding tree units of the current picture,-   wherein the data encoder (110) is configured to partition the    current picture such that there exists no row among the one or more    rows of the current picture where any coding tree unit of said row    is misaligned,-   wherein the data encoder (110) is configured to encode the original    picture data of each of the plurality of tiles of the current    picture independently from the original picture data of any other    tile of the plurality of tiles of the current picture,-   wherein the current picture is partitioned such that there exists no    row among the one or more rows of the current picture where any    coding tree unit of said row is misaligned,-   wherein the original picture data of each of the plurality of tiles    of the current picture is encoded within the encoded video signal    independently from the original picture data of any other tile of    the plurality of tiles of the current picture.

Example 123: A system comprising:

-   the video encoder (101) according to example 33 or 34, and-   the video decoder (151) according to example 77 or 78,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 124: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture, wherein the reference picture precedes the    current picture in time,-   determining a motion vector of the current picture depending on a    motion vector of the reference picture and depending on how the    current picture is partitioned into the plurality of tiles of the    current picture, and-   encoding, depending on the motion vector of the current picture, the    original picture data of each of the plurality of tiles of the    current picture independently from the original picture data of any    other tile of the plurality of tiles of the picture.

Example 125: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture,-   wherein the plurality of pictures comprises a current picture and a    reference picture, wherein the reference picture precedes the    current picture in time,-   wherein the method further comprises:    -   determining a motion vector of the current picture depending on        a motion vector of the reference picture and depending on how        the current picture is partitioned into the plurality of tiles        of the current picture, and    -   for each picture of the plurality of pictures, decoding,        depending on the motion vector of the current picture, the        encoded picture data of each of the plurality of tiles of the        picture independently from the encoded picture data of any other        tile of the plurality of tiles of the picture to obtain original        picture data of the plurality of coding tree units of each of        the plurality of pictures.

Example 126: A computer program for implementing the method of example124 or 125 when being executed on a computer or signal processor.

Example 127: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture and has a position within the picture, wherein the    plurality of pictures comprises a current picture and a reference    picture, wherein the reference picture precedes the current picture    in time,-   wherein a motion vector of the current picture depends on a motion    vector of the reference picture and depends on how the current    picture is partitioned into the plurality of tiles of the current    picture, and-   wherein the original picture data of each of the plurality of tiles    of the current picture is encoded within the encoded video signal    depending on the motion vector of the current picture, encoded    independently from the original picture data of any other tile of    the plurality of tiles of the picture.

Example 128: A system comprising:

-   the video encoder (101) according to one of examples 35 to 38, and-   the video decoder (151) according to one of examples 79 to 82,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Example 129: A method for encoding a plurality of pictures of a video bygenerating an encoded video signal, wherein each of the plurality ofpictures comprises original picture data, wherein the method comprises:

-   generating the encoded video signal comprising encoded picture data,    wherein the data encoder is configured to encode the plurality of    pictures of the video into the encoded picture data, and-   outputting the encoded picture data of each of the plurality of    pictures,-   wherein the method further comprises:    -   for each picture of the plurality of pictures, partitioning the        picture into a plurality of tiles comprising a plurality of        coding tree units of the picture, wherein each coding tree unit        of the plurality of coding tree units comprises a plurality of        samples of the picture,    -   for each picture of the plurality of pictures, encoding the        original picture data of each of the plurality of tiles of the        picture, and-   wherein generating the encoded video signal is conducted such that    the encoded video signal further comprises a first flag that    indicates for a current picture of the plurality of pictures,    whether a reference picture of the plurality of pictures being    different from the current picture has been used for encoding the    current picture.

Example 130: A method for decoding an encoded video signal comprisingencoded picture data to reconstruct a plurality of pictures of a video,wherein the method comprises:

-   receiving the encoded video signal, and-   reconstructing the plurality of pictures of the video by decoding    the encoded picture data,-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein the encoded video signal further comprises a first flag that    indicates for a current picture of the plurality of pictures,    whether a reference picture of the plurality of pictures being    different from the current picture has been used for encoding the    current picture,-   wherein, for a picture of the plurality of pictures, decoding the    encoded picture data of each of the plurality of tiles of the    picture is conducted depending on the first flag to obtain original    picture data of the plurality of coding tree units of each of the    plurality of pictures.

Example 131: A computer program for implementing the method of example129 or 130 when being executed on a computer or signal processor.

Example 132: An encoded video signal encoding a picture, wherein theencoded video signal comprises encoded picture data encoding thepicture,

-   wherein, for each picture of the plurality of pictures, the picture    is partitioned into a plurality of tiles comprising a plurality of    coding tree units of the picture, wherein each coding tree unit of    the plurality of coding tree units comprises a plurality of samples    of the picture,-   wherein, for each picture of the plurality of pictures, the original    picture data of each of the plurality of tiles of the picture is    encoded within the encoded video signal, and-   wherein the encoded video signal further comprises a first flag that    indicates for a current picture of the plurality of pictures,    whether a reference picture of the plurality of pictures being    different from the current picture has been used for encoding the    current picture.

Example 133: A system comprising:

-   the video encoder (101) according to one of examples 40 to 44, and-   the video decoder (151) according to one of examples 84 to 88,-   wherein the video encoder (101) configured to generate the encoded    video signal, and-   wherein the video decoder (151) is configured to decode the encoded    video signal to reconstruct the picture of the video.

Although some aspects have been described in the context of anapparatus, it is clear that these aspects also represent a descriptionof the corresponding method, where a block or device corresponds to amethod step or a feature of a method step. Analogously, aspectsdescribed in the context of a method step also represent a descriptionof a corresponding block or item or feature of a correspondingapparatus. Some or all of the method steps may be executed by (or using)a hardware apparatus, like for example, a microprocessor,a programmablecomputer or an electronic circuit. In some embodiments, one or more ofthe most important method steps may be executed by such an apparatus.

Depending on certain implementation requirements, embodiments of theinvention can be implemented in hardware or in software or at leastpartially in hardware or at least partially in software. Theimplementation can be performed using a digital storage medium, forexample a floppy disk, a DVD, a Blu-Ray, a CD, a ROM, a PROM, an EPROM,an EEPROM or a FLASH memory, having electronically readable controlsignals stored thereon, which cooperate (or are capable of cooperating)with a programmable computer system such that the respective method isperformed. Therefore, the digital storage medium may be computerreadable.

Some embodiments according to the invention comprise a data carrierhaving electronically readable control signals, which are capable ofcooperating with a programmable computer system, such that one of themethods described herein is performed.

Generally, embodiments of the present invention can be implemented as acomputer program product with a program code, the program code beingoperative for performing one of the methods when the computer programproduct runs on a computer. The program code may for example be storedon a machine readable carrier.

Other embodiments comprise the computer program for performing one ofthe methods described herein, stored on a machine readable carrier.

In other words, an embodiment of the inventive method is, therefore, acomputer program having a program code for performing one of the methodsdescribed herein, when the computer program runs on a computer.

A further embodiment of the inventive methods is, therefore, a datacarrier (or a digital storage medium, or a computer-readable medium)comprising, recorded thereon, the computer program for performing one ofthe methods described herein. The data carrier, the digital storagemedium or the recorded medium are typically tangible and/ornon-transitory.

A further embodiment of the inventive method is, therefore, a datastream or a sequence of signals representing the computer program forperforming one of the methods described herein. The data stream or thesequence of signals may for example be configured to be transferred viaa data communication connection, for example via the Internet.

A further embodiment comprises a processing means, for example acomputer, or a programmable logic device, configured to or adapted toperform one of the methods described herein.

A further embodiment comprises a computer having installed thereon thecomputer program for performing one of the methods described herein.

A further embodiment according to the invention comprises an apparatusor a system configured to transfer (for example, electronically oroptically) a computer program for performing one of the methodsdescribed herein to a receiver. The receiver may, for example, be acomputer, a mobile device, a memory device or the like. The apparatus orsystem may, for example, comprise a file server for transferring thecomputer program to the receiver.

In some embodiments, a programmable logic device (for example a fieldprogrammable gate array) may be used to perform some or all of thefunctionalities of the methods described herein. In some embodiments, afield programmable gate array may cooperate with a microprocessor inorder to perform one of the methods described herein. Generally, themethods may be performed by any hardware apparatus.

The apparatus described herein may be implemented using a hardwareapparatus, or using a computer, or using a combination of a hardwareapparatus and a computer.

The methods described herein may be performed using a hardwareapparatus, or using a computer, or using a combination of a hardwareapparatus and a computer.

While this invention has been described in terms of several embodiments,there are alterations, permutations, and equivalents which will beapparent to others skilled in the art and which fall within the scope ofthis invention. It should also be noted that there are many alternativeways of implementing the methods and compositions of the presentinvention. It is therefore intended that the following appended claimsbe interpreted as including all such alterations, permutations, andequivalents as fall within the true spirit and scope of the presentinvention.

REFERENCES

ISO/IEC, ITU-T. High efficiency video coding. ITU-T Recommendation H.265| ISO/IEC 23008 10 (HEVC), edition 1, 2013; edition 2, 2014.

1. (canceled)
 2. A hardware apparatus for video encoding, the hardwareapparatus configured to: encode a first flag for a segment of a currentpicture into a data stream, wherein the first flag indicates whetherblocks of the segment are intra-predicted only, meaning that the blocksof the segment are predicted based on reconstructed samples of thecurrent picture only; responsive to the first flag indicating thatblocks of the segment are intra-predicted only, encode a second flaginto the data stream that indicates whether or not a current block ofthe segment is encoded using intra block copy (IBC), wherein when thecurrent block is encoded using IBC, the current block is predicted bycopying samples from a reference block of reconstructed samples of thecurrent picture; responsive to the second flag indicating that thecurrent block is encoded using IBC, determine a prediction of thecurrent block by copying samples from the reference block ofreconstructed samples of the current picture; and encode a predictionresidual into the data stream based on the prediction of the currentblock.
 3. A hardware apparatus for video decoding, the hardwareapparatus configured to: decode a first flag for a segment of a currentpicture from a data stream, wherein the first flag indicates whetherblocks of the segment are intra-predicted only, meaning that the blocksof the segment are predicted based on reconstructed samples of thecurrent picture only; responsive to the first flag indicating thatblocks of the segment are intra-predicted only, decode a second flagfrom the data stream that indicates whether a current block of thesegment is encoded using intra block copy (IBC), wherein when thecurrent block is encoded using IBC, the current block is predicted bycopying samples from a reference block of reconstructed samples of thecurrent picture; responsive to the second flag indicating that thecurrent block is encoded using IBC, determine a prediction of thecurrent block by copying samples from the reference block ofreconstructed samples of the current picture; and reconstruct thecurrent block based on the prediction of the current block and aprediction residual decoded from the data stream.
 4. A method of videoencoding, the method comprising: encoding a first flag for a segment ofa current picture into a data stream, wherein the first flag indicateswhether blocks of the segment are intra-predicted only, meaning that theblocks of the segment are predicted based on reconstructed samples ofthe current picture only; responsive to the first flag indicating thatblocks of the segment are intra-predicted only, encoding a second flaginto the data stream that indicates whether a current block of thesegment is encoded using intra block copy (IBC), wherein when thecurrent block is encoded using IBC, the current block is predicted bycopying samples from a reference block of reconstructed samples of thecurrent picture; responsive to the second flag indicating that thecurrent block is encoded using IBC, determining a prediction of thecurrent block by copying samples from the reference block ofreconstructed samples of the current picture; and encoding a predictionresidual into the data stream based on the prediction of the currentblock.
 5. A method of video decoding, the method comprising: decoding afirst flag for a segment of a current picture from a data stream, thesegment encoded into the data stream, wherein the first flag indicateswhether blocks of the segment are intra-predicted only, meaning that theblocks of the segment are predicted based on reconstructed samples ofthe current picture only; responsive to the first flag indicating thatblocks of the segment are intra-predicted only, decoding a second flagfrom the data stream that indicates whether a current block of thesegment is encoded using intra block copy (IBC), wherein when thecurrent block is encoded using IBC, the current block is predicted bycopying samples from a reference block of reconstructed samples of thecurrent picture; responsive to the second flag indicating that thecurrent block is encoded using IBC, determining a prediction of thecurrent block by copying samples from the reference block ofreconstructed samples of the current picture; and reconstructing thecurrent block based on the prediction of the current block and aprediction residual decoded from the data stream.
 6. A non-transitorydigital storage medium having a computer program stored thereon toperform, when the computer program is run by a computer, the steps of:decoding a first flag for a segment of a current picture from a datastream, wherein the first flag indicates whether blocks of the segmentare intra-predicted only, meaning that the blocks of the segment arepredicted based on reconstructed samples of the current picture only;responsive to the first flag indicating that blocks of the segment areintra-predicted only, decoding a second flag from the data stream thatindicates whether or not a current block of the segment is encoded usingintra block copy (IBC), wherein when the current block is encoded withIBC, the current block is predicted by copying samples from a referenceblock of reconstructed samples of the current picture; responsive to thesecond flag indicating that the current block is encoded using IBC,determining a prediction of the current block by copying samples fromthe reference block of reconstructed samples of the current picture; andreconstructing the current block based on the prediction of the currentblock and a prediction residual decoded from the data stream .
 7. Anon-transitory digital storage medium having a computer program storedthereon to perform, when the computer program is run by a computer, thesteps of: encoding a first flag for a segment of a current picture intoa data stream, wherein the first flag indicates whether blocks of thesegment are intra-predicted only, meaning that the blocks of the segmentare predicted based on reconstructed samples of the current pictureonly; responsive to the first flag indicating that blocks of the segmentare intra-predicted only, encoding a second flag into the data streamthat indicates whether or not a current block of the segment is encodedusing intra block copy (IBC), wherein when the current block is encodedusing IBC, the current block is predicted by copying samples from areference block of the current picture; responsive to the second flagindicating that the current block is encoded using IBC, determining aprediction of the current block by copying samples from the referenceblock of the current picture; and encoding a prediction residual intothe data stream based on the prediction of the current block.